I have an 07 Chevy Silverado 1500 two wheel drive with the 4.8L V8. I am usually a proud owner of my cars and trucks but this here Chevy is a disappointment! I have great amounts of problems one of them being rough idle. When it is cold it runs just fine but take it out for a drive and things change! I can have it in my driveway in park or at a light in drive and you can feel the motor running rough. you can also watch the tac and see the rpm's fluctuate. Now keep in mind that its not doing this 100% of the time but to put it into a percent I would have to say 90%. Yes I had taken it to the shop and guess what NO CODE was found! Thats all the dealership did was run codes and that was that. YES problem is still there!

The 6.0L MAX Vortec Chevrolet engines seem to have a rough/missing idle. Numerous forums have other owners stating same issues. My selling Chevy dealer service rep stated that GM knows about the problem but cant correct due to fuel/EPA regulations. Fuel mixture must run lean, thus missing idle. Annoying at best, especially since no fix. Was told by dealer service rep that using power programmer such as Hypertach, Diablo, Edge etc would nullify warranty. GM makes an engine that they cant even tune right them will void warranty if you fix their mess up...go figure. Another fine GM product! No wonder they are losing market share...they still dont get it yet...stand behind your products...if you have a known issue then state it to buyers before they flop down their hard earned cash!