I have a 1999 Chevy Silverado 2500 4x4 ext. cab with the 6.0l which as my title says, has an idle issue. I bought the truck about 3 years ago and about 6 months in I started to have a bounce to the idle. Whenever I stopped at a stop sign or light, the rpms bounce from 500 to 400 or 300 hundred then back up. This continues until I give it gas. The first time it happened there was a check engine light, I took it to a shop and they found it was the fuel pressure regulator so they replaced it. A few months passed and it started doing it again but this time there is no check engine light so I cant figure it out. I thought maybe the egr valve isn't functioning properly or the throttle position sensor is going bad but I just want to be sure that Im not missing the obvious. Sorry for the long thread I just want to give as much info as possible. Thanks for any input!

 

have you checked fuel pressure and volume?

 

No i havent. Ill have to give that a try. Thank you!

 

Might be worth to change the fuel line if still haven't in a long time. Update us