Rough idel
Safety Car
Joined: Feb 2002
Posts: 4,212
Likes: 10
From: Sun City West Az
Re: Rough idel (ZQQM)
1991 L98 has 39,000 original miles, what are those parts you mentioned? :withstupid:
Melting Slicks
Joined: Jun 2002
Posts: 2,168
Likes: 16
From: Phoenix AZ
Re: Rough idel (ZQQM)
Wow, low mileage for a '91. I wouldn't think that your TB (throttle body) would be too filthy with less than 40K miles. THe IAC is the Idle Air Control solenoid. It is located on the pass side of the TB and it controls how much air the engine gets depending on what the other sensors are telling the ECM that the engine is doing. If it gets grunged up it can't do its job and can result in the type of problem you are describing. Did you have any other work done to the car recently where they might have disconnected a vaccum line or something? That's where I would look first. Check all of your hard plastic vaccum lines and make sure that (1) they are all connected; and(2) none of them are broken. You can also check for vacuum leaks by waving an unlit propane torch around the suspicious areas, if the idle speeds up, you have found your leak. Make sure to follow all of teh vaccum lines as far as you can, sometimes they come unplugged in back of the engine below the distrubutor or other places where it is hard to see.
Melting Slicks
Joined: Jun 2002
Posts: 2,168
Likes: 16
From: Phoenix AZ
Re: Rough idel (vetracer)
Got your e-mail. How many RPM's do you see on the tach at idle? Is it consistently the same RPM at idle? Do the RPM's drop to idle speed right away or does it take a few moments?
