high idle speed
try unplugging the leads from the idle speed valve to see it it is working at all. It should speed up. One thing that will cause high idle speed is a failed temperature sensor--though this will usually bring the RPM up to 1000 or so. Air leaks (cracks)in the rubber 'housing' on the bottom of the air flow plate will also cause this problem, though usually 'leans out' the mixture too much unless you have O2 sensor system.