Every morning especially, when its cold, after the engine warms up about half way, my h23 starts revving up and down between 1k-1500rpm. This difference becomes samller and smaller (then 1200-1400... smaller). Also after a 90 mile trip, after I got off the highway, at idle it started doing it again. What could be the problem. Also, after I drive the car for a little bit in the mornings (.5-1 mile) the problem goes away. Also, the engine idles rather high a lot of around 900-1100 rpm. Other time its fine.

 

im pretty sure it is a vacuum leak.... but do a search and you will find more threads on this subject

 

What vaccum leak. You mean like IM leak?

 

keep an eye on your temp. gauge cuz it could be radiator. mine had a similar problem
also have the valves been adjusted at all recently

 

Fast idle valve

 

The temp is ok. The gauges are digital so it is hard to see how much it is going over even it is. The digital bars are always at the middle. The problem though is that I thought the problem was oly in the morning when the car is cold, but it also happend after a long highway trip when the engine was hot (warmer than usual because of long distance). Would the radiator probllem cause this wierd idle when the engine was cold? Regarding the idle control vavle.... that is what my mechanic thought it might be without looking at the car. How much does it usually cost to fix that problem.

Thanks for all the help