Ranger 04 4.0L V6 issue

I have an 04 Rander Edge 4.0L V6. A few months ago I noticed when I traveled a short distance (either stay in 1st gear or up to 2nd gear before slowing down) the idle stays up above 2000 rpms. I just shoved it off until this past weekend when it did it all the time, and come to realize it that it is even when I driven long distance. I also noticed that it is more then just comming to a stop (where I would take it out of gear and coast in by tapping the brake) but when I switch from a lower gear to a higher gear the rpms jumped up to 3000 rpms. Some variables I've been able to knock off... It happens when the vehicle is cold and warm so it's not due to cold starts.... It happpens when the Heat is on or off (not sure if it happens when A/c is on though).

The only thing I can think of is recently I switched to synthetic oil instead of regular oil. Can't remember if I had the issue when I did the switch or not and I've been using synthetic for about 4 months now and didn't have nearly as much problems as I do now.

I took it to ford but long behold it isn't happening for them, but I do have to say it wasn't happening to me this morning either.

Has anyone else seen this with their ranger?

it happens to me too, i have a 95 4.0L 5 speed. sometimes it revs up to 2grand and sometimes 3grand and just stays there until it eventually comes down by itself. it dosent matter if the engine is hot or cold, or what gear its in, but as soon as i put the clutch in there it goes. i dont know what causes it but it pisses me off!! and its starting to do it while driving now, while in gear if i let off the gas it idles up and maintains speed as if the cruise control was on. and i have replaced the throttle position sensor, if anyone can shed some light i would appreciate it :smile: