IAC - sits on the throttle body and passes air for idle. Mine failed just
like yours. I think they're about $30 at autozone.
If the rough idle continues after you give a little gas - this may not be
it. How new are plugs and wires?
Hope this helps - PoD
I have a 1990 Mercury cougar with a 3.8 v-6 and all of a sudden I cant keep
the car running. It sounds like it's running on only 3 cylinders. When I
give it a lot of gas it seems to straighten out, then as it idles down it
runs real rough again and stalls out. I cant keep it running. The wires look
fine. This car was running fine and all of a sudden this happened out of the
Any suggestions on what to look for first?