If you have a scanner that can read the ect and iat in degrees, get a reading from these two sensors in the morning after the car sat overnight, turn the key to on, do not start it, readings should be within 5-10 degrees of each other. My money is on the ect. But if you have a bad idle at all temps, even warm, remove the idle air control valve and clean or replace it. You may have a vacuum leak, 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!
Friday, April 11th, 2008 AT 3:12 PM