I just bought a 1998 2WD Ranger with a 3.0L V6. It has what I'm seeing is a common problem where the idle remains high for several seconds after the clutch is depressed and the transmission is taken out of gear. It eventually settles down to about 750 RPM but for about 5-6 seconds it will sit at almost 2000.

I want to do a thorough investigation of the vacuum system as a first step. I'm asking for the input of some of you with some experience about where the most common vacuum leaks are? I've done a quick look and I can't see any degraded rubber hoses. Do any of the diaghrams have a tendancy to leak?

 

is this at start up? whats the temp gauge say? I believe if you had a vacuum leak the idle wouldn't settle down.