It looks as if Ill need to start saving for a complete AFM delete kit with a new cam. Any truth to that? GM Releases Valve Lifter Service Update For V8 Engines How is that an improvement. whith a disabler. module (ECM) will command the cylinder deactivation system ON to deactivate engine cylinders1, 7, 6, and 4, switching to a V4mode. Another General Motors 5.3L V8 Lawsuit Filed | GM Authority Is this an issue only with GM SUVs and trucks, or does it include cars too? 2019 Chevy, GMC Trucks Get Smarter Cylinder Deactivation - Car and Driver Im curious as to how much tran fluid you put in? All Cylinders. Have misfire code and engine has what I would call a surge while driving. [], [] rugged iron block 6.0L came with VVT, but without Active Fuel Management, which saves you the cost of an AFM delete [], [] The LH6 engine is a 5.3L Gen. IV aluminum engine that replaced the LM4 in 2005. How long did it take? Having it fixed now, just curious Seems like a problematic design. For fun, he runs his 427-powered C5 Z06 in ECTA land-speed racing, at OPTIMA street car events, and at a mix of autocross, drag racing, and track days. A lot of drivers reported losing 2-4 quarts of oil in between oil changes. I just did the delete and replaced the cam as well. Took it to a shop and they advised that it could be due to the AFM system not functioning properly. As you said, the ECM was never seeing the AFM so I think youre good to go. a little burning oil is a minor thing, my main concern is avoiding a multi-thousand dollar repair needed to the motor. Because your Saab is mechanically similar to the Trailblazer, wed suggest that you are correct and no changes need to be made to the relief valve. I have also heard that the oil pump is to be changed and I have also heard that it does not matter. He used seafoam and changed to synthetic oil. Also, it is the easiest way [], [] for the 2010 Chevy Camaro SSis also a Gen IV 6.2L aluminum-block V8, but with the addition of Active Fuel Management and Variable Valve Timing. I am having that done today on my 08 Suburban and its only costing me $225. Just like Ram and their trash MDS system or Ford and their throwaway Ecobust engines. RANGE TECNOLOGY.COM. I switched from gm to dodge in 1984, have had 3 1st gen Durango and 4 2nd gen Dakotas, all used, with impeccable reliability. Right now I have just over 77K miles with no lifter problems Knock on wood I am thinking of the AFM disabler. In the mean-time I found that you can keep the engine from going into 4 cyl mode by using the manual shift (if so equipped) and keeping it out of 6th gear. GM Escalates Cylinder Deactivation With Dynamic Fuel - EngineLabs Replaced all 16 lifters due to collapsed lifter on CYl #4. Only thing I noticed with the oil consumption issue. Most of all, my concern is reliability. Active Fuel Management (formerly known as displacement on demand (DoD)) is a trademarked name for the automobile variable displacement technology from General Motors.It allows a V6 or V8 engine to "turn off" half of the cylinders under light-load conditions to improve fuel economy.Estimated performance on EPA tests shows a 5.5-7.5% improvement in fuel economy. I already ordered the parts to replace myself and remove the code. Should I buy one to disable the V4 mode? It seems to me that the high volume oil pump should not hopefully cause premature wear but if it is pushing more oil through the heads than I guess the valve stem seals have more work to do. The cherry on top is its not saddled with Variable Valve Timing (VVT) or Active Fuel Management (AFM) found on some Gen. 4 engines. My dad ended up running seafoam through it and some transmission fluid, changed the oil pressure sensor which I definitely think was bad and also cleaned out the little screen and he said it was so full of junk and metal scraps. I love the car so far. I have a 2013 1500 with the LC9. If I had wanted a 4 banger I would have bought one. Should I buy a Diablo AFM disabler to prevent the new block from dropping to 4 cylinder? Call chevy.They should being paying most of that. We recommend taking the truck to a local chassis dyno tuner and talking with them about a reflash. Cylinder deactivation is very effective in reducing fuel and reducing the emissions of harmful gases. She drove it for another 35,000 and it went out again. I ave noticed the point about excess oil spray. Some drivers want V8 power under their foot at all times. Just one or two. 1. Or not because it is the cast iron block and not he aluminum block? AFMis good for gas mileage and can be 5-7 percent more fuel-efficient under certain conditions. When we removed the oil pan from the new block, we noticed a metal shield covering the bottom of the block. The Oil pressure relief valve deflector added in Oct. of 2010 is small and its part number is NAL-12639759. 91 GMC Sierra K1500 F44 6.2 NA Plow truck with 7.5ft Leo Plow 94 K3500 CC DRW 6.5TD DE exhaust . It prevents the computer from switching over to four-cylinder mode. Hello Keith, if your lifters are still in good shape, an AFM Disabler is a good idea. Getting 20 mpg in town and 24-28 mpg highway and love the truck now with these mild tweaks. However, they are only functional on engines that usedAFM. I have a shop 39 yrs . 1. The oil collapses the plunger inside the lifter. It replaces the AFM components with standard parts. Im crossing my fingers it does the trick! Why cant u just unplug the solenoid on back of engine by oil pressure sensor? Does cylinder deactivation affect engine life? - Quora Pulled right valve cover an rockers on syl 6 dont move. No movement on the rocker arms. General Motors Active Fuel Management Cylinder Deactivation Technology Active Fuel Management (AFM), otherwise known as Cylinder Deactivation is a General Motors engine technology that. It is replaceable.. just remove oil pan and it will be on top at the filter. The engine also had 799 or 243 casting heads which are closely related to the LS6. The valve itself is part number W0133-2574213. $8500.00 fix. It is currently at the dealer having a new long block installed under warranty. I traded in a 2004 4.8 L with 256000KM on it that ran like a clock and never gave me a problem. Last GM Ill ever buy unless its got a diesel. Accept i only have 60K on my truck and it hasnt recovered. Below youll see references to the L99 as a result. I am considering the same. GM Dynamic Fuel Management Cylinder Deactivation Technology - GM Authority Then I guess I have to spend a bunch of money and get the delete kit. The only solution is to replace the entire cylinder head. But it also restricts passages that the oil runs through. With 40000 Required fields are marked *. The trucks are only supposed to use two four. The LFA was upgraded with AFM and [], [] improvement over AFM, DFM has 17 different cylinder firing patterns and switches seamlessly between them to provide just []. Here are a few of the issues that you'll want to keep on your radar if you drive a 2017 Chevy or GMC vehicle with a 5.3L engine in it. I am leaning heavily on installing the AFM disabler. On June 4th you stated The vehicles affected were 2007 to Feb. 2011 AFM equipped engines (Aluminum or Iron block-L94, LZ1, L99, LC9, LH6, L76, LFA, LMG, and LY5) I am looking at purchasing a 2012 Tahoe with the LMG per the build sheet. [] Here is a guide on how to turn off AFM: https://www.onallcylinders.com/2017/11/30/how-to-delete-or-disable-active-fuel-management-afm-on-gm-… [], [] Guide to disabling AFM: https://www.onallcylinders.com/2017/11/30/how-to-delete-or-disable-active-fuel-management-afm-on-gm-… [], [] Here is an article on how to deactivate AFM. it is the regulator guy! Ayush Srivastava September 2017, I got talked into trading for 2017 AFM this was a bad choice 5.3 engine. The 2016+ Tacomas are junk. I sold them when they were new. With that said, the current global chip shortage has been affecting the industry on a wide scale, forcing production halt among several automakers. More information can be found in the GM TSB bulletin number 10-06-01-008g. I have a 2011 GMC Sierra 1500 with the 5.3. Been driving with no issues but I did notice that the AFM disabler removed a P0449 code (Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction) dont know if this is a coincidence or they are related??? The biggest problem is nobody changes their oil on time. A problem with the software caused the engine to idle with most of their cylinders, thus overheating the exhaust . You were lucky that it worked. Traded it with 180K miles and did not experience any problems. is it still working good since you have done that with the trans fluid? From what Ive read new and low mileage engines with no issues is ideal to do a afm delete, tune, or use of a disabler. I contacted service manager in Gastonia, NC and he was kind enough to tell me the whole history of the problem.. EPA required better fuel mileage and less emissions and GM, Ford and Honda(V-6) came up with this failed AFM system. They learned that the oil level sensor was necessary and that we were supposed to have been advised that we needed to reuse the original oil pan. [], [] Its a Gen. 4 5.3L iron-block engine, so youre getting the better intake manifold, connecting rods, and ECM. [] For more on that, read: How to Delete or Disable Active Fuel Management (AFM) on GM Engines. I can tell you for the past 2 years I changed out my LC9 5.3L fully synthetic oil every 3,000, even though Mobile Oil claims 10,000 miles or more. I have an 07 Silverado 1500 ltz. What would you do if you were in my situation? This reduces expense when you build it [], [] intake, and a cable-driven throttle body, plus Im also installing Trick Flows VVT and AFM delete kits. Its a simple and effective way to turn off the AFM system and provides the added bonus of improving exhaust sound. Truck ran fine before that. In 2010, GM added a deflector (p/n) NAL-12639759 to redirect in into the pan. GM get a clue! Not sure which direction to go from here. On one hand it has an aluminum block, which is nice. Now the problems back, I have 180k miles on it now. 2014 Chevy, GMC Pickups Recalled For Cylinder-Deactivation Issue HP tuners is not for someone like me that doesnt know how to use it and from what I read neither the range nor diablo plug and play device will work since the buicks pcm files are different than all other GM vehicles that came with afm because it was tuned in house at gms performance division. Active Fuel Management About Gone From 2022 Silverado Lineup - GM Authority I just bought a 2015 5 3 17000 miles I was thinking about eliminating the 4-cylinder if I delete it with just the programmer will it hurt my motor? You may eventually see a check engine light from a misfire code and the ECM dialing everything back to protect your engine. As the problem gets worse, youll hear a lifter tick and eventually you may see clearance between the pushrod and the rocker which will quickly destroy the cam. I have only put about 600 miles on it and noticed that the oil was a bit low and am hoping that it was that way when I picked it up. I pulled the head off, replaced the lifter and put the gadget in the ODBII for about $400 total. You mentioned that it will shoot oil into the pan and on the cylinder walls possibly causing some oil consumption So i have a running vehicle and my only concern is making it as reliable as possible, should I disable the AFM or not?? Learn how your comment data is processed. I recently bought a 2018 Silverado 5.3L with AFM. When cylinders are deactivated, the number of crankshaft rotation increases between firing pulses. Keith, were happy to help. Are there errors or something only the dealer can clear? The engine had 200K miles. There are 5.3 cylinder deactivation problems that can occur. Verified over hundreds of trips, makes no sense. Now I know why there wa such a push to get older ,less efficient vehicles off the roads. Toyotas 5.7 is one of the biggest gas guzzlers among half-ton trucks. After taking a $3.6h bath on the lifter/valve work and doing a little research, how can GM allow a problem like this AFM continue from 07 to present? [] they have a downside? My Wifes 17 Buick with afm was my attempt to get back to gm. Stop-start cylinder deactivation, direct injection, variable valve timing, thermal management, and continuously variable oil pump; are just some of the Silverado features of . I am going to do the full repair of the engine now, but not an overhaul (too hard to get at the pan). All Gen IV engine blocks haveAFMtowers and oil passages cast in. Brian, I repaired a 2012 GMC Yukon Denali as the AFM lifter on #4 I take failed. Love the truck. I couldnt agree with you less, yet I respect your opinions. Every one of these engine will have a lifter fail, this is a travesty! .or something similar . Driver reported this occurred suddenly while driving down the highway. Bought an 07 GMC Yukon 5.3 with the AFM, 87k. The tune is the best bang for the buck outside a cam swap anyway and what Id recommend. Now I get 24 to 26 with deactivation locked out and full power. It is also known as Displacement on Demand (DoD) or cylinder deactivation. Chris, when you did your delete, did you also change the cam at the same time? It seems this tough engine has everything incorporated into it. My 2013 LC9 just had #6 lifter fail, got a misfire code but the ticking gave it away. i have a 2007 suburban 6.0 and the number 4 intake lifter took a dive.i have already started to disassemble the engine as i plan on replacing all the lifters and reassemble the engine as i never had any other problems with it. But then she passed away from cancer. Side note, after 200 hundred miles of trouble free driving the transmission failed so we had to replace that too. My 5.3 is. What the biggest reported problem with Chevy Silverados? I have a 2011 GMC with over 162,000 miles on it and it runs great! There is a filter screen under the oil pressure sender that may be clogged and not getting enough oil to supply the solenoids. Now I learn about the cylinder deactivation issue and suggestions to add the Range Technology module to deactivate it. I have a 2008 Buick Lacrosse super that I am having a hard time finding a tuner or a tune shop that can turn off the afm. Fouls those plugs. I speak from some experience. According to CarComplaints.com, several drivers have had excessive oil consumption issues for a while from 2007 to 2011. I wont bother with blocking the relief valve. Can I (should I) also change to a standard volume oil pump? I am not in a position to have a new cam and lifters installed but Im also not in a position to not having a running truck! There is a chance the cam lobe was stressed and started to deteriorate. [], [] way. Looking for another Toyota at this point to match my 1985 4 runner with 380.000 miles and no issues since new. I have 217,000+ on it and it never fails meever! When an engine is contstantly running on oil that is broken down, it not only wheres out components because of no protection. I didnt have lifters fail, I had the 4 cylinders 1,4,6,7 have such blow by that my choice was a valve and piston job or a new motor. Is the Pressure relief valve replaceable? Any problems to watch out for?Did you replace the VLOM? If buying a tuner/chip which works best for that truck/engine? Hello. http://www.autoserviceprofessional.com/article/91652/ticking-gm-v8-lifters-and-dtc. Thanks for the advice Brian! [] cherry on top is that it isnt saddled with Variable Valve Timing (VVT) or Active Fuel Management (AFM) found on some Gen. 4 engines. Have there been improvements in more recent model years employing AFM [2014 or newer]? Would you get enough power to drive at freeway speeds? For a primer [], [] cathedral port cylinder heads and used Active Fuel Management (AFM). But if you dont like it. Got rid of the bobblehead Rancho offroad shocks immediately and replaced with Bilstein coil overs. The Cylinder Deactivation system, known as the Active Fuel Management system by GM, shuts off some of the cylinders when extra power is not needed which improves fuel economy. I also notice that it doesnt go into V4 when it is cold. The motor I pulled was a 2007 LY5 with about 77k on it. The pressure relief in the pan opens at around 45psi to prevent over pressurization of the vlom solenoids. Seafoam with syn oil change only fixed for a week. It does seem that when they start goingthey go quickly. On the AFM lifters that dosnt work i have installed them With the oil hole Down! thanks brian love the info Im thinking of buying a ford now, I am going to buy a new truck in about a month it would be a Chevy but Dodge has lifter problems so they are out and Chevy has DoD problem.If they come out with Silverado without the DoD then i would buy one.But they arent so i will become a Ford man from now on, Have fun with that Ecobust motor & stretched timing chain . Question i just bought a 2005 Saab 9-7 with 5.3 v8, (same as GMC envoy) which came with AFM, the car runs fine, so if i just install the OBDII electronic device, is it just as likely that my lifters will still go bad? At this state, a disabler would probably do what you need it to do. Vortec 5300s featuring LH6 and LC9 engines are prone to failing spark plugs due to carbon build-up. Never did strand me on the side of the road way. another common cause for low OP is the oil pick up tube O ring. AFM works by deactivating half of the engines cylinders under certain circumstances to reduce fuel usage. Dont follow just anybody I know where it originates but in todays world I found found it to be amusingly accurate. Anyway that horrible experiment was in the late 70s early 80s along with those converted Diesel engines..those like the 8-6-4 nonsense were just terrible failures. One must anticipate this. CHANGE YOUR OIL!!!!! Disable Active Fuel Management - Ricks Free Auto Repair Advice In 2015, I purchased a new Tahoe with the AFM and two weeks ago with 71K miles on it, the engine light came on. When they are locked into position, they wont wear further and cause issues down the road. If you think GM pioneered cylinder deactivation, guess again Constant engine and transmission problems. This should be added to your earlier model if you experience oil consumption. We have purchased a used low mileage 6.2L as that is all the extended warranty company would pay for. This lowers the cost of building it [], [] aluminum block engine. Thanks to a properly maintained 5.3 with AFM, I can routinely get over 20 MPG on the highway. You can search our site by engine code to find some of the upgrade articles weve published and more are on the way. Toyota will be my next truck unless GM owns up and makes wright with consumers. I loved this rtuck until this happened!! I hate it. The LZ1 was upgraded with AFM and []. This new lawsuit is essentially identical to the previous. I had a 2007 Yukon XL 5.3 with the AFM. This system is the most effective way to disable AFM. I have had some say that it is the valves and others say that it is the cats plugged. Theyre also notorious for bad cam tower oil leaks. My 2012 Silverado 5.3L just did the same thing as your Tahoe Brian. I have a 12 wit 4.8 Silverado 75000 miles (Bought car 1 day before lifter died!) It had the AFM wiring & lifter cover installed with solenoid pack in the original engine, we even removed it to inspect. As long as a lifter hasnt started to fail, you can get by with a less-expensive disabler as preventative maintenance. That might show up if you cut the filter and looked for debris in the pleats. I have been assuming this is just a slow to pump-up lifter or lifters. The problem I am facing is that I want to drive this vehicle for at lease another 77K and do not want to drive my vehicle with this AFM issue. I am trying to prevent same issue. The engine is close siblings with the LMG which shared many of the same featuresexcept the LMF isnt saddled with AFM. The Tundra fares better but the frame has the rigidity of wet spaghetti and the 5.7 has had problems with VVT solenoids and the plastic timing chain tensioners. [] block engine used in GM hybrid trucks and SUVs between 2008 and 2009. I saw two Summit Racing kits, with different valley coverswhich one do I need for my Yukon? Service manager said nothing else needs to be replaced because the engine has a Teflon coating. I would. They shift cam lobes by sliding the cam, never actually shutting down the value but riding a different lube! A 17 with 5.3. It has 8,000 miles on it. 2015 SILVERADO 1500 44 crew cab with 5.3L engine: So two weeks ago with approx 70K miles, I had an odd noise when accelerating and then engine light flashing and riding rough. Can you tell me what needs to be done with the VVT? Do not pay that amount. I went with the new motor for the warranty. I am hoping this does the trick. Per bulletin 10-06-01-0007b, 2007 L92 had first and 2nd design. Batten, followed by several years developing performance pistons at Wiseco Piston Co. Today, Brian develops performance parts for Summit Racing Equipment and is a regular OnAllCylinders contributor. I have a 08 6.0L out of a Silverado with an aftermarket oil pan that has no provision for a pressure relief valve. Chevy Silverado V8 To V4 Problems - Tools Bible Happened once 1yr ago, truck was not used for a week and worked fine when i started it back up. Pod. Any guidance would surely be appreciated. My point is that the engine likely on uses dod a small percentage of the time so can not really imagine that the delete causes any more issue than normal which may be the high oil consumption but do all of these engines with dod consume a lot of oil? Carbon Build-Up in the Intake Ports. Will the plug in deactivater fix the oil consumption or will it cause more consumption? There are so many more oil passages on engines these days. The GM 2.7-liter L3B Turbo four-cylinder engine for Chevy Silverado and GMC Sierra pickups is meant to change minds about power and torque in a small package. . Oh,the throw away vehicle has 77,000 miles and has always had meticulous maintenance . If you dont have VVT, you could use part number NAL-12561721 (LQ9) along with a 4-pole 3-bolt 2005 Corvette cam sprocket p/n NAL-12586481 to make it compatible with your ECM. December 20, 2021 A GM lifter recall should allegedly be ordered for Buick, Cadillac, Chevrolet and GMC vehicles equipped with 5.3L, 6.0L or 6.2L V8 engines. Driving around with a bad AFM lifter is the fastest and easiest way to destroy an engine. 190k on the motor always ran AMSOIL full synth since new. What was happening to the first is slowly (or quickly in your case) happening to the others. Sometimes it will do it all the time and other times can drive it for 10 miles and then it starts but doesnt do it constantly when driving. My 2011 Tahoe has a LMG motor in it with a build date of May 2011. Plus the 5.7 has its own problems with VVT reliability and the rest of the truck is flimsy junk. Next day, fired it up to take the the junk yard and it ran great. Replaced the engine with remanufactured one and had the AFM turned off with a computer hooked to the ECU. We are looking into the AFM Disabler option, but my question is- how do we know if a lifter is already bad or not? They are being forced by the feds to use stuff like AFM to meet the CAFE requirements. If I were to put a 2006 5.3L in a 2007 Avalanche and buy the unit to plug into my OBD2 port would it work? On the caddis it helped to relocate the computer inboard the passenger compartment to keep them cool helped . They layed over night in engine oil before instalation. Covers me to 100K. AFM or active fuel management is a GM/Chevy technology meant to improve gas mileage. My 2002 I had over 298K on it with no engine related issues. Billy, there is some interesting trivia here on the L92. Teflon coatings does not last. Ive been a Ford guy my whole life, so I was unaware of AFM until a recent trip where I did a lot of highway driving and happened to bring up the real-time mpg display, where I saw it switch between V6 and V4. The Jury is still out on the Gen. 5s but the warranty could be an issue. It has has 9000 miles and no lifter or other issues or codes so far. Cylinder Deactivation to the Rescue. I have no other engine problems and Id like to fix the issue. I have an 08 Suburban that is currently getting the lifters replaced a second time within a three month span. Took the heads off again. Oil 0w or 5w -20 My 97 k2500 suburban with a lightly modified 6.5L diesel gets 20ish. Thank you. Shame this happened. We recently purchased an 08 Suburban and noticed some shuddering around crusing speeds, usually 45-55mph and highway speeds around 75mph. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); This site uses Akismet to reduce spam. Im always sorry to hear when people run into issues like these. All the time. Hi Brian please help, yesterday after ice fishing was climbing a hill back home and check engine light flashed. We had one for a company car in 82 and it never did run right from new but at least it didnt destroy itself. Dale, I have a 08 Tahoe thats doing the same thing.Any info you have on this would be appreciated, [] Do they have a downside? My tech just installed the engine, only to notice that he doesnt have anything to plug the AFM solenoid pack into. Corvette that does employ AFM. The Hit and Miss Nature of Cylinder Deactivation Systems An AFM Disabler is an electronic device that plugs into the OBD-II port, under the dashboard. They are taller and have special oil holes. I am wondering the same thing. TheAFMsystem can be identified by its components. im going to plug in a dissabler when im done to keep it V8 mode all the time. Now you tell me AFM works and I will tell you; that you are full of shit! You can unplug the sensor on the vacuum booster and it will fool the computer into thinking there is a high demand on the engine and shut down the AFM system but you will have a Check engine light in your face for doing so . Engine starts but is throwing a misfire on cyls 4,7. Are you saying that I am in the clear by a year and issues fixed? Vehicle has been serviced more regular than the manual calls for and the AFM has caused problem after problem with fouled plugs. The biggest difference between the Vortec engines that used to be found in Chevy and GMC vehicles and the EcoTec engines found in them now are the fueling methods. Anyway, after some pushing and pulling I took it to the Dealer who sold it to me. Thanks for the detailed post! . I have seen more internal engine failures in the last 5 years or so than I have in the first 15 years in the business. Regards, PDF Service Bulletin Bulletin No.: 20-NA-038 Date: March, 2020 GM should recall every vehicle with this terrible design flaw! Oil flows to the special lifters through theAFMtowers. From what I am reading this would eliminate the possibility of failure, prevent false check engine lights and continue to make the appropriate power??? Ketil, let us know what you find out. Id wait until the warranty expires then disable. Still have no power. I only have ~ 5k miles on it, and it hasnt been driven hard, so Im assuming the lifters are fine. Chevrolet Silverado 2014-Present: Common Problems Interesting that gm still hasnt gotten the bugs out of their Volt and now their 2nd attempt. Found that all passenger side cylinders are not firing. Thankfull for any ideeas! Clean oil is crucial. There is a note in the TSB that states the bulletin doesnt apply to the LH6 used in the Rainier, Trailblazer, and Envoy due to a different design oil pan and AFM relief valve. We figured we already had the intake manifold off to install the engine, why run the risk of MIL only to have to removed the intake manifold again without being paid. Changing the sensor didnt help. As GM issued 13 updatesnone of which workeddealers disabled the system on their customers' cars, leaving them permanently in V-8 mode. HELP, I have 2005 envoy that runs makes lifter noise then dies in about 30 seconds then I started it one day and it ran with little noise for 5 min started next day and it starts and dies again got heads off was told I could put ls 3 lifters in is that true or is there something else I could do thanks Duane. No other truck my ass .lol my 99 silverado 1500 with the junk LR4 4.8l and 320k miles 9n itgets 21mpg all day long with 93 octane gas in it. One month to the day driving on the highway got the Service Stabiltrak message quickly followed by the misfire code.