Last post on Nov 26, 2013 at 5:54 PM
You are in the Chevrolet Silverado & GMC Sierra
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GMC Sierra 1500, Chevrolet Silverado 1500, Fuel System, Truck
#348 of 415 2011 sierra with afm/mileage issues
Mar 13, 2013 (10:20 am)
My2011 sierra 5.3 afm gets 16-17mpg around town or highway.it 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 mine.im starting to think some of these have an inherent problem, with software or whatever. Id like to hear from others about performance/fixes etc.
#349 of 415 Follow up on Chevy 5.3L w/AFM
Mar 26, 2013 (4:13 pm)
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.
#350 of 415 V8-V4 Fixes
Mar 26, 2013 (5:04 pm)
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.
#351 of 415 Re: Follow up on Chevy 5.3L w/AFM [msw007]
Apr 02, 2013 (3:22 pm)
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.
#352 of 415 Re: Follow up on Chevy 5.3L w/AFM [msw007]
Apr 02, 2013 (5:21 pm)
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.
#353 of 415 2009 Silverado 5.3L w/AFM
Apr 03, 2013 (10:50 am)
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).
#354 of 415 No more afm for me
Apr 03, 2013 (8:14 pm)
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.
#355 of 415 Re: No more afm for me [jswain2]
Apr 04, 2013 (5:31 am)
I personally think you made a wise decision. Best of luck with your new ride.
#357 of 415 AFM JUNK!!!!
Apr 10, 2013 (4:45 pm)
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. My GMC