2000 3.0L high rpm between manual shifts

2000 3.0L suddenly began to maintain high RPM when shifting through the gears. Still drops to proper idle speed at stop, and throttle return spring is strong. Any ideas of what could be causing this?

I just went thru the same thing on my 95 3.0. It was a vacuum leak, it was on the hose going to the carbon canister. I was told to check everywhere for vacuum leak, mainly around intake. Spray hoses with Gumout with truck running & you will tell difference in idle when you spray leak. I also cleaned out my IAC too, but it didn't solve problem. Mine would rev up by itself while idling & return to normal, also would hold rev inbetween shifts. Check for vacuum leak 1st.Good Luck