I have a new issue will my 03 Chevy 6.0. When the truck is cold it idles rough. Doesn't actually feel like a misfiring cylinder. In gear at a stop light the idle will drop below 500 rpm and the engine...
I received a letter from GM on my '09 6.0 about rough idle quite a few years ago. If my mileage was still under 100,000 and the rough idle happened the letter said to bring it to the dealer. Of course I had over 100,000 on my truck by the time I got the letter.