amac,
I, also, was thinking either: the coolant temp sensor, the air temp sensor (on the intake hose), or maybe a failing ignition module. I tried to get to the coolant temp sensor yesterday, but that bugger is hard to reach, beneath the throttle assembly. I will try again, to see how that goes. I will also check the air temp sensor.
Oh, one other thing about that coolant temp sensor: Haynes shows pics of it, and they tell how to check it, but they only mention one with two wires. Mine has three. Anyone know the proper way to check this?
Question for anyone: What is the hose going into the upper left corner (as standing in front and looking at engine) of the intake plenum? I know it is a vacuum line, and I know that when I take it off, the idle is so bad the car almost stalls, but the other end doesn't go anywhere. Where is it supposed to go?
This could be related to my problem, as the line itself is cracked and broken in a couple of places.