Rough Idle

MSUChevyMan · May 15, 2004

I've got a 99' Silverado 5.3L with a rough idle that's quite annoying when I have to sit with it running in park for very long. I have replaced the plugs and am going to change the wires here soon. My brother had a 00' Silverado with the same problem and he had someone clean out the EGR or ERG valve(I forget what it's called) Does anyone know where it is and if it's something I could do on my own? Thanks

GMCTech · May 15, 2004

Cleaning the EGR may help, I would also clean out the throttle body, and check to see if all the available software updates have been done.

GM has numerous software updates available to address this exact concern as well as other minor drivability propblems.

Hope this helps.

Shaners · May 17, 2004

Like TECH said I'd look at the throttle body first, and then also at cleaning the MAFS

97whitez71 · May 17, 2004

May want to try running Sea Foam through it. Only about $6. A lot of people have used Sea Foam and it smooths the idle out. Just another, cheap, idea.

rcj_houston · May 17, 2004

From my past experience, if the EGR is starting to go bad, or dirty in my old bronco's case, the engine will surge. Like, rev up and down while at idle. All I had to do was take the egr apart and clean it with B12 Chemtool and it worked for another 6 months.

I think the other guys are on it that commented. Definitely start with the throttle body. I also rea somewhere on here that there is a passage on the inside of the trottle body that can get clogged. I honestly can not remember where the post is

Good luck and let us all know if it works.

cheers