I've had the same problem and had a lot of work done, including replacing injectors, plugs, oxygen sensors, etc. The rough idle continued until I studied the repair manual and discovered the idle control valve. For a car this old, it was never replaced. I ran down to AutoZone and bought a new one with warranty and replace it. The rough idle immediately disappeared and the engine is so quite know at idle, I hardly notice it. This may not be your problem, but the fact that you have an 89 and have tried other things points to it Generally owners neglect this inexpensive part after many miles of driving.
Saturday, October 29th, 2011 AT 11:45 PM