I would take out the Idle Air Control Valve, then take the throttle body off and clean the throttle body and the port for the IAC out good. You may even want to replace it unless they can test it at the auto parts store. Same with the EGR Valve, take it off and clean the carbon off and make sure it works. Also just snug up the intake manifold bolts.
Try checking your timing and make sure the distributor is tight
Weather its cold or warm on startup it idles rough then rpm goes up to 1500 and smoothes out and runs great, idles good after that.
1995 GMC Sierra 1500 C1500 SLE Extended Cab Stepside SB
-
Maintenance & Repair
Truck has started idling really rough when, say, stopped at a light. The idle continues to be rough when I pick up speed, but it tends to even out a little. On top of that, my coolant has been disap...
1990 GMC Sierra 1500
-
Maintenance & Repair
why does my 98 Sierra idle rough between 1st and 2nd gear,? it's 2wd runs good once it gets out of 2nd,gears switch right on with the rpms at 2,500. what could our be.?
1998 GMC Sierra 1500 C1500 SL Extended Cab SB
-
Maintenance & Repair
When "Reducing power to engine pops up on the console, the accelerator doesn't work so i pull over and turn off the trucks engine and wait a minute and the truck goes back to normal. At first the Ch...
2004 GMC Sierra 1500 4 Dr Denali AWD Extended Cab SB
-
Maintenance & Repair
Idle is very rough. If you blow it out carbon pours out of the exhaust. But it starts idling rough again.
2005 GMC Sierra 1500
-
Maintenance & Repair
Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.