I have an '01 Ranger with the 2.5L engine, with about 140k. The truck runs well, sans one issue that I have been having lately (which may, or may not, have gotten worse as I turn the A/C on) - engine idle.
I had the problem 4 months ago, and then it simply stopped. Last week it came back: Whether I am stopping at an intersection, or driving at any speed, the engine idle will sometimes climb. If I throw the truck into neutral, and hit the accelerator pedal, the engine idle will sometimes return to normal, although lately when I punch the pedal, the idle will climb when I hit the pedal, and stay high. The only thing that seems to reset the idle, is (while the truck is running and in gear) - clutch in, ignition key off, and back to run.
My vacuum lines look good, and the throttle cable isn't binding. Check engine light is off, and the other than this, the truck drives and (otherwise) idles fine.
I am not the most technical guy in the world, but any suggestions would be greatly appreciated. Thanks!