Check all the vacuum lines for cracks.
Look at the injector seals, make sure they are seated properly.
Check the intake manifold gasket.
Car is equipped with an idle air control valve, it is mechanical, located under the throttle body. I have to say that these rarely go bad.
There is an idle adjustment screw but, DO NOT ADJUST it until you find the vacuum leak.
I just had the same problem on a 91 Corolla, turned out to be the intake manifold gasket.
Tuesday, September 29th, 2009 AT 9:25 AM