THIS IS A GM DESIGN FLAW! THIS IS GOING TO BE MORE APPARENT IN THE COMING MONTHS AS THESE 2007-2009 MODEL YEARS START CREEPING UP ON THE 75K-85K SWEET SPOT MILEAGE. GM IS TRYING TO HIDE THE FACT THEY HAVE A PROBLEM AND HAVE A BANDAID SOLUTION. YOU CANNOT CHECK IT WITHOUT A COMPLETE TEAR DOWN OF THE MOTOR. IF YOU HAVE THE 5.3L MOTOR WITH AFM I WISH YOU LUCK. MY STORY IS BELOW: 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. I find it pretty amazing when they want billions of our tax dollars to bail them out and I'm looking for $700 just does not compute with me. Feel free to share this and let's set GM straight that they should stand behind their product!!!!