high rev/idle on 1990 D21

[cyclops2101]

My 1990 D21 has a high rev/idle problem which comes and goes. There are times when driving and the clutch is engage, I can hear the engine idle very high. When in gear and driving, everything is normal. I flushed the cooling system, cleaned the throttle body with the trottle body cleaner and checked for any vacuum leak and nothing was found. Again, it comes and goes but gets to me especially when driving on a rocky/dirt road and need to hold the clutch pedal halfway or else the high rev comes or the high rpms pushes the car too fast on the bad road. Need help to find the problem. I don't have a book but I will order it. Truck has been in the family since new and has about 121K miles on it. Thanks

[chrisagu28]

Not to bring up a old post but check the ecu under the set and make sure the idle screw is set low.

just check it sorry again.