2.5l revving when clutch pressed

[lindsay_elaine]

My mom's boyfriend bought an '01 reg. cab a few weeks ago with a 2.5 and 5 speed and 215k on it. He has barely driven it since he got it (it's used mainly for running to the dump) so I drove it around today while running errands just to see what it's like in comparison to my '03 2.3. Four out of five times, when I pressed the clutch in, it would rev up to 3k and stay there for about 5 or 6 seconds, then drop back to idle. It did this all day, and towards the end of the day, it was revving up to 3500, dropping down below idle to the point of almost stalling, then going back to idle again. This kept happening without my foot being anywhere near the gas pedal. It revs up between shifts too but it's less noticeable than when you're coming to a stop with the truck revving itself. Any ideas? It's pretty annoying when you're sitting stopped at a crosswalk with your engine revving, makes ya look like a jerk, lol

 

[Duane867]

Fuel filter could do it, air filter could do it, pcv ( maybe ), vacuum leak....