I have been having a issue with the way my car idles, I used to think this was just to a heavier flywheel on the car, but now im starting to suspect something different, usualy when you start the car from a cold start it will idle high then come down a little bit, this will not. I got stuck in a traffic jam today on the highway, and the idle would not come down below about 1500 rpm, the only way I could get it to go down would be to let the clutch out a little bit, which would bring the idle down to normal, but as soon as I rev the motor back up it will go back to its odd idle. What should I look for?