2011 GMC Sierra with 115,000 miles just bit the dust --- dealer tells me it needs a new engine due to the active fuel management --- I cannot believe GM won't step up and admit fault and take care of this issue BEFORE the engine fails. There was no sign of a problem until the "service stabilitrac - service traction control" light started going off, so I took it in to my local dealer to see what was going on and a mis-fire in the engine (of which you cannot tell by driving it) was causing the light to come on. So I drove in with what seemed like a perfectly good truck and now a new engine is required. COME ON GENERAL MOTORS - WHEN ARE YOU GOING TO HELP OUT THE CONSUMERS OF THIS FAULTY MOTOR DESIGN ??????? CASE # 8-3990972607 - you know how to contact me.............

Welcome to the forums. Sorry to hear about your Sierra'* Problems/AFM & misfire related issues.
We are not in anyway related or affiliated to General Motors & I suggest that you continue to pressure GM directly regarding your case & to obtain help $ for repairs..

Unfortunately once you are out of warranty, and misfires are experienced, GM will either help out or not. I wish you good luck with that.

Proper diagnostics regarding the misfire/* must be conducted to determine the actual root cause. It may be best to have a different shop do further assessments.

The AFM lifters can be problematic/fail and oil consumption then becomes an issue.
Turning off AFM is possible on some engines, during the rebuild process.
Consulting with a good engine shop for the rebuild, may prove to be successful.
How to Delete or Disable Active Fuel Management (AFM) on GM Engines - OnAllCylinders

Thanks for the support Soft Ride; my truck is currently at a GMC dealership, so taking it elsewhere at this point would only be adding $$$. Turning off the AFM on the next engine at this point is not an option --- dealership says they do not know the "technical" side of this type of programming and they basically don't want to be involved, so then the engine would have a warranty but anything after that would be on me if things go south again. Between a rock and a hard place........thanks to GM.

Why does it need an engine replacement?What is the failure? Why can't it be repaired?Was a cost comparison done? Was it run through the Good Will calculator to see what GM will do
to participate? Was the engine using oil? Is it noisy? Is it more cost effective to replace than repair? So many questions,so little information.
I have repaired many of these. I have seen Gm participation on many out of warranty repairs. As for disabling the AFM. It'* not worth the fine given to the repair facility or mechanic for emissions tampering.

As I initally posted : "There was no sign of a problem until the "service stabilitrac - service traction control" light started going off, so I took it in to my local dealer to see what was going on and a mis-fire in the engine (of which you cannot tell by driving it) was causing the light to come on. So I drove in with what seemed like a perfectly good truck and now a new engine is required."
The dealership says the AFM is to blame (oil starvation in the lifters) there are 2 weak cylinders and a 3rd. with a bad lifter/roller which has scored the cam. The cost to repair my engine was more than the cost of a rebuilt engine; and the warranty is better on a rebuilt engine as well. Rebuilding my engine would be a 12 month warranty and a rebuilt engine has a 3 year/100,000 mile warranty. I currently have a case number with GM and working with a senior advisor for some $$$ support/compensation.

Now it sounds like you have a diagnosis of a bad cam and lifters. Most of the time you hear a dry rubbing noise (as best as I can describe the distinctive noise a you hear with the failure you describe)and a cost comparison. The Dealer has a program where thy can input the numbers and it tell them how much GM will participate in the repair. If that'* not satisfactory I've seen the Advisor and The Service Manager Contact the AVM and plead your case. That seems to be Hit or miss. I don't blame you for the frustration and wish you the best

Got a call from GM last week --- I will be getting NO help from them. Obviously they do not care about loyal GM customers. They know this is their fault and do not want to accept responsibility. I will be visiting the FORD and DODGE dealerships for my next truck.

Where I am sure you will still experience some sort of hardship.

I'm curious:

How many of the 115,000 miles did you own the truck?

What were your oil change intervals?

What part of the world does your truck live in?

What kind of driving did it mostly do (off-road/towing/city/highway/etc.)?

None of this will solve much on your vehicle. I'm just trying to have a sense of trends that may be related to this issue. Probably will be useful on the board as time goes on.

I'd also be curious how your experience with your next vehicle goes if you don't mind checking back in with us every once in a while in the "Lounge" as it appears the next vehicle will be non-GM . Best of luck!