1993 Geo Storm

Engine Performance problem
1993 Geo Storm 4 cyl Front Wheel Drive Manual 150000 miles

The engine won't idle right; sometimes when I let off the gas coming to a light it won't drop below 2000/2200 fluxuating somewhat rapidly between the two, and after 20 seconds or more it will finally drop to normal, but then (sometimes) fluxuate between 500/1000.
Sometimes it will race from a normal idle up to 2200 then back down to normal with a real jerky ride.
I put a new ICM on, and it wouldn't drop below 4200 so I returned it, and put the old one back on.
I don't know what to do without spending a bunch.

Thank You
June 12, 2010.

Clean and test the idle air control valve and the throttle position sensor.

Jun 13, 2010.