You might start with several wax idle valves. By blocking these inlet
valve you can tell which is causing the problem.

Resetting your computer can make your idle drop another 500 rpm. If
your idle is at 750 warmed, ignore this.

> i just bought a 1992 Accord Dx with 130,000 miles. When it warms up
> and is in park the idle changes from 1,500 to 2,000 rpm. It revs as
> it changes though, its not gradual. The car rides fine except for
> this. Does anyone know what ithis problem is?