First thing is are there any engine modification? Or air intake mods? If not check for vacuum leaks. Get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody. If you have one of the oil soaked air filters, change the MAF, cleaning wont work! I have done a few of these for this, and Chevy has a TSB on it.
Friday, August 15th, 2008 AT 2:36 PM