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Chevy Silverado and GMC Sierra Active Fuel Management Problems



  • The dealer has had my truck for over a week now trying to fix the collapsed lifter problem. They have changed the lifters the oil poppet valve and the inlet screen on the lifter control module and it still is not fixed. The only thing they have not replaced is the control module. The first time it went in for the problem they changed the lifters and it worked for about 8,000 miles before it did it again. The second time it cleared up and they said they could not reproduce it. Now the truck is past the 5 year point on the warranty. Since the problem was never fixed properly when it went in the first time shouldn’t it still be covered under the warranty?
  • Yes, it should still be covered. If they can pull up in the computer where a problem was noted before warranty expired, they should still cover it now.
  • Update… It took two weeks to finally get my truck back. I had to go to the dealer and talk to the service manager and the mechanic to tell them how to fix the problem. They had changed out all of the fuel control lifters, the poppet valve and inlet screen to the valve control. Basically they had changed everything in the system except for the controller with the four solenoid valves in it. I explained to them that the only thing left to do was to change the controller assembly. After they finally changed it out the system worked just fine. I went directly to the service manager when I went to pick the truck up and had a chat about how it should be covered under warranty because the problem was never fixed correctly the first time they had it he changed the invoice and GM paid for the repair. If it comes back again I’m dumping the truck and getting the diesel 2500 or getting a Ford. I’m done with the crappy GM fuel management system.
  • They covered it but only after I forced the issue.
  • chuck1chuck1 Posts: 1,405
    Unless you really need the pulling power of a diesel, the fuel and maintenance costs are prohibitive IMHO. Look at a Ford F150 w/the 5.0 or the Tundra or Dodge w/their biggest gas motors.
  • wvhotshotwvhotshot Posts: 5
    edited March 2013
    Update: After I got the truck back it has no low end power, a miss that it didn't have before and at hwy speeds the RPM is 400 higher than before. The engine also feels like it has a surge when driving down the hwy almost like it stops firing for a split second. The gas mileage has also dropped by 4mpg. I took it back and they had it for a week and then changed out the torque converter saying it was locking up too soon???? When I picked it up on Saturday and drove it and nothing was fixed from before but now when driving in slow traffic it feels like the thing has a stall speed converter in it. From a rolling start the engine revs up before the converter engages and you here it when it does go into engagement thru the drivetrain. They reprogramed the computer after doing the lifter work. Did GM make changes to the programing for the transmission shifting points and converter lockup? It is now the 4th week they have had the truck and all I keep hearing is “we don’t know what’s wrong with it?” Please help
  • I need the pulling power. That is why I got the MAX tow package truck with the 6.0L.
  • msw007msw007 Posts: 21
    So I would like to discuss our recent troubles with our 2007 Chevy Tahoe LT 5.3L. We were finally able to purchase our first new car, 2007 Chevy Tahoe LT, ever in October 2006 from our local dealership. We decided on the Chevy Tahoe because we have had a used Chevy Suburban and Used Chevy Tahoe prior and have had excellent experience with both of them. It was truly a wonderful experience until now.

    Flash forward to October 2012. While traveling several warning lights came on “Service Traction Control, Stablitrak, and Service engine”. We brought it to the dealership a few times to scan for a code and they couldn’t come up with anything. So now we had to wait until it was actually happening and rush it over to the dealership so they can scan for the code while it was happening. Finally it was happening enough that we were able to get it to the dealer for the scan. The scan revealed that spark plug #1 was fouled and would cause a chain reaction on all the computers to go haywire. So they did a little research and they found a GM TSB (technical service bulletin) that said replace the valve cover gasket, replace all the plugs and wires. Keep in mind these are 100K mile platinum plugs/wires and we currently have around 79000 miles on the vehicle (GM recommends replacing these items at 100K miles). So we did what we were told and $700 later we were on our merry way.

    Jump forward to January 2013. Now we start hearing a clunking sound on acceleration. We bring it back to the dealer and they can’t seem to find anything (of course not????). Now February the sound is more apparent and all the warning lights have come back. I decided to take the car to a friend of mine who has a local shop and specializes in foreign autos. I knew he would take the time and do the research to finally tell us what the dealer couldn’t. After having the car for a week the verdict was in. GM has this fuel management system introduced on this particular 5.3L motor in 2007. It’s supposed to be able to switch from 8 to 4 cylinders and back to help save on fuel (Active Fuel Management or AFM). To confirm the problem he would have to tear down the engine and check the intake valve on cylinder #1. This is when I said “I’m taking it back to the dealer”.

    Now the dealership has the car and I didn’t mention that I already had it looked at. I wanted to see if they would come up with the same diagnosis. Well after a week they did. I can’t believe it since the initial $700 fix 3000 miles ago in November 2012 I now have to replace the engine, WTF! Needless to say I was not a happy camper. Now the car has been out of warranty for a little over a year (which has been pointed out to me over and over again) but that’s not the point. The point is we bought a brand new car so we wouldn’t have any problems usually associated with used cars. A car that has less than 100K miles on it. A car that has been religiously serviced by our local Chevy Dealership. And now I’m being told I have to replace the motor!

    The dealership called GM. GM was quick to say they would replace the motor and cover 50% of the costs? Well whoop de doo. Why were they so quick to offer that deal? Of course they are replacing it with a genuine GM remanufactured motor with a 3 year/ 50K warranty and that’s all they are willing to do. I don’t expect the dealership to cover all the costs and it would be nice if I wasn’t out of pocket any. Yes I know the car it out of warranty but I expect GM to back up their product. Did I mention I have purchased over $100K in new Chevy vehicles over the last several years.

    So the car is no good to us. Can’t drive it, sell it or trade it in. I basically have to take the deal. My estimated out of pocket will be $3K plus tax.

    So I decided to call GM directly and talk to them in a kind Christian sort of way (as only I can do). I figured if they heard from the customer directly that they would be willing to at least come down a little. I know the car isn’t under warranty. The results were not what I was looking for. After they gathered all the information from the dealership and me as well they will only cover 50% of the cost. I explained to them that I’ve been a loyal customer, this car had less than 100K miles on it, I’ve spent over $100K in Chevy cars over the last several years. Nope all they would do is 50%. I asked would they would at least reimburse me for the $700 that I already spent that was totally unnecessary? Nope only 50%. Well let’s just say things went pretty much south from there.

    So here is where we stand. The dealership is putting in the new motor. They are working with me to get the price down under $3K. I don’t begrudge the dealership I think they did what they could do (as personally later found out with GM). I don’t begrudge the lady at GM I’m sure she has set parameters she has to follow and she’s just a drone in the corporation. However I do begrudge GM for not standing by their product. Do the research it’s all over the internet. GM has a problem with this motor and it’s “Active Fuel Management” they know it and they will continue to have problems. Unfortunately if you do have this particular motor there’s no way to check if you will have this problem or not. I will never buy a GM product again. They have lost a loyal customer over $700.
  • chuck1919chuck1919 Posts: 176
    How long do you think GM should be responsible for your car? 3000 dollars is a deal for a GM backed motor-take it!
  • churchy25churchy25 Posts: 12
    Dumb question. Of course it's a good price....a good price on a new motor that should not have to be purchased for a vehicle with 80k miles. When the vehicle goes out of warranty u understand that maybe u will need to repair an alternator, battery, fuel filter, fuel pump, oil pump, etc. u don't expect to replace a damn motor. AND if u r the only person with this problem, it would make it easier to swallow having to pay for such a repair. But when u see this problem is rampant and GM is hiding from it even though they know the AFM has a serious design flaw, it really pisses people off. They lost my future business for ever with almost the exact same story as above. I've bought a new chevrolet truck every 4-5 years since 94. No more. EVER! And I tell everyone about this design flaw and what GM actually does about it. My sister actually bought a Ford Edge instead of a Chevy Traverse simply because of my experience. It's a shame. It's not the same Chevrolet that my dad was a fan of.
  • msw007msw007 Posts: 21
    I agree with churchy25. I could see replacing some minor things under 83000 miles but to replace an entire motor??

    This is a GM design flaw and they are hiding behind the warranty issue. I have never argued the fact that $3000 for the motor was not a good deal. I just want GM to admit they have a bad design flaw and they have to take care of it. I'm sure GM is betting on the come that these motors will start failing after 100K miles and then they can say too bad so sad to the consumer.

    The problem is these motors are failing at an alarming rate at 50K miles with 75K-85K being the sweet spot for failure. So cars my age are starting to get to that mileage and pretty soon there are going to be a whole lot of pissed off consumers out there.

    If you have your heart set on a GM vehicle (2007 and newer) with this motor then I strongly urge you to purchase the extended warranty.
  • kmt3kmt3 Posts: 2
    My2011 sierra 5.3 afm gets 16-17mpg around town or has a hard time staying in 4cly mode even at 45mph.several times its run 55+mph and had no problem staying in 4cyl mode also showed very good mpg on instant readout.sometimes aroundtown it will do same, but get it in v8mode it will not return to state of operation as before.been to dealer and had it checked out-everything ok.ive heard rumors of these trucks running 6o+mph on 4cyls and 20+mpg also heard about a lot like starting to think some of these have an inherent problem, with software or whatever. Id like to hear from others about performance/fixes etc.
  • msw007msw007 Posts: 21
    Well we have the new remanufactured motor installed.
    I spoke with the mechanic at the dealership and asked what exactly happened and if this was normal?
    He told me the rings on the piston were worn and caused the leak by which fouled the plug. The cylinder wall were scarred and the other cylinders were starting to look worn.
    He just shrugged his shoulders when I asked him if this was normal (that kind of says it all right there).
    I know Black Bear Performance offers a tune solution to turn the AFM off. I guess they started to offer this due to the rash of complaints and problems that have been associated with this.
    I have sent letters off to GM's upper management pleading my case. I'm not expecting much but it doesn't hurt to try.
  • chuck1chuck1 Posts: 1,405
    There is a company called Range Technology that sells "black boxes". They sell one that will either keep you in 4 cylinder mode longer or one that keeps it in V8 mode only. They plug in to your diagnostic port AND LEAVES NO TRACE ON THE ECM.
  • msw007msw007 Posts: 21
    So I received a phone call from GM Corporate (my letters got through). I have spoke with him several times and as of now GM is holding firm on the 50/50. They say because I accepted the deal there's nothing else they can do? I reminded him I accepted the deal because I had a useless car and it had to be fixed (holding a gun to my head).
    I told him right up front I'm not looking to get off without paying anything. I understand the car was out of warranty but the fact of the matter is the engine failed under 100K miles.
    He said there were a few more upper management people he could plead my case to. So I don't know if he's blowing smoke up my a** or he's being truthful. We'll see.
  • chuck1chuck1 Posts: 1,405
    Be glad you got a motor at 50% off and move on. We have seen your posts just like this one on several other boards.
  • jboehmjboehm Posts: 44
    Reading the boards it looks like I am just starting this process, but thought I would add my story as well. I have a 2009 Silverado with 41k miles on it. I noticed over the winter that my idle had gotten pretty rough (to the point that the check engine light came on a couple of times) so I did some research and found issues with the #1 and #7 plugs becoming fouled. Figured the next time I did an oil change I would mention it and see what the dealership wanted to do. Over this last weekend I was driving home when I heard some major clicking noises coming from the engine. Since I needed an oil change anyway I dropped it off at the dealership and mentioned the rough idle and clicking noises. The end result was that the #1 and #7 plugs were cracked so they replaced that and also put on a redesigned cover. I did buy a GM extended warranty just before the 3/36 expired (glad I did) but have to be concerned about where this may lead me to. Especially when I read that motors are being replaced at 80k - 85k miles.

    I let the oil life monitor tell me when the oil needs to be changed but since I bought the truck new I have done generally 9 months between changes but this last time it was barely 6. When I mentioned that they also want me now to come back every 1k miles to do a consumption test.

    Love the truck, have a warranty to cover issues but have to deal with the hassles (and the possibility of a engine replacement right after the extended expires).
  • jswain2jswain2 Posts: 16
    I traded my truck in tonight. Won't say what brand, it doesn't matter. It's not gm.

    I kept hearing lifter tick and spark knock which had gotten a little worse and I was tired of worrying about the lifters and hoping it wouldn't start burning oil. I'd had enough. I hope I have good luck with this one, and I hope all the 5.3 owners have good luck. I, personally, would not recommend buying a gm vehicle with afm. Too many reports of issues, too much worry. But if you do get one or have one, I wish the best for you. Here's to all of us staying out of the service department for a long time. Other than maybe a free oil change.
  • I personally think you made a wise decision. Best of luck with your new ride.
  • mr_pinkmr_pink Posts: 3
    I bought an 07' GMC Vortecmax 6.0 SLE a year and a half ago with 60,000 miles on it. I pulled out of my driveway this winter, and you know "what" hit the fan. To make a very long and depressing story short. I have a misfire on cylinder #1 which shut off my stabilitrak and traction control, also my oil manifold needs replaced. I took it to a dealership, they quoted me 2100$ for just the left bank repair, and 3400$ for both banks, all gaskets,bolts,manifold etc.... I still owe 15k on it and am sort of stuck paying for a rolling paperweight. I have no warranty since it now has 112k miles on it and its 6 years old. God bless GM for making vehicles last just over a 100k so the unexpected blue collar worker has a hard time finding a ride to and from work, my next vehicle will not be a GM made product. :lemon: My GMC
  • mr_pinkmr_pink Posts: 3
    To all the Idiots on the first thread that were saying " My 6.0 max runs flawlessly." and " My wife thinks I love my truck more than her." I bet now that there has been time on you're trucks it isn't running so well. My 07 max has 112k and the AFM failed all the way across the board.
  • jswain2jswain2 Posts: 16
    Thanks, bro. I gotta say it was quite a relief getting shed of the afm. I'm loving the new truck right now, but I have less than 1k miles. I hope it gives me good service. It's all 8, all the time. And I like it that way. I owe $12,500 after trade in and rebates and some dealer wrangling. But, for now, I'm under warranty and don't have that sickening feeling of impending mechanical failure. Again, good luck to all with afm issues. I have been there. Geez I hope I never have to talk to another service manager.
  • dmm8dmm8 Posts: 1
    I really wish someone had warned me about the AFM engine before we bought our 2010 Silverado. That truck has been amazing up until the past few months. We are currently on our 3rd oil consumption test and they still haven't officially diagnosed what the issue is. I've been reading a lot lately about the AFM engines burning through oil or the oil pumps going out, which would make sense. Had I known about these problems before we bought it....we would have gotten a different engine. The whole point to having a new vehicle, is to have a reliable vehicle. Now I'm afraid of my truck dying every time I stop because the oil pressure drops so low. :(
  • gmcustsvcgmcustsvc Posts: 4,251

    Please keep us updated on your oil consumption test and diagnosis. If there is anything we can do please let us know.


    Amber N.
    GM Customer Care
  • chuck1chuck1 Posts: 1,405
    These motors (good or bad) run with very little oil pressure. IT'S NOT ONLY YOUR TRUCK. THEY ARE ALL THIS WAY.

    If you wish to turn off the AFM-invest $200.00

    I know you shouldn't have to spend to do this, but the dealer will not turn off the AFM for you.
  • cmezumcmezum Posts: 1
    junked the afm!
    installed mild street cam, texas speed push rods, new lifters, mild ported the heads, valve job, and dual springs installed, ls7 valley tray, long tubes and y pipe, intake, and tune. 260whp stock
    estimating 70-90 whp increase. going to strap it to the dyno today for the tune and final numbers.
    Would still be stock if GM had designed it better.
  • chuck1chuck1 Posts: 1,405
    With the range device owners are reporting oil consumpion issues being much less with the V8 only range device.
  • chuck1chuck1 Posts: 1,405
    How does rebuilding the motor to different specs affect the emissions?
  • jframejframe Posts: 5
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