engine revs weird and loses power when warmed up

I bought this 89 Ford F-250 the other day with 111,000 miles on it. It runs good, but I notice if you push the gas pedal down a 1/4 of an inch, it revs up to 2000 and stays there for about 10 seconds. I can't seem to sit there and hold an Rpm between 800 and 2000RPM. This makes shifting an experience. I also noticed that when its cold it runs great, lots of power, nice and smooth, as soon as it warms up it seems to spit and sputter a little at low rpm's and doesn't have any power. It has a 351 with a 5spd. I think it will be a good truck once these issues are taken care of. Anyway I hope somebody on here has been through this and knows the problem. I am thinking it may possibly be the throttle postion sensor but I don't know if that would cause all of it.

Thanks, Dan

are you burning though oil or collant? You might have bad rings(?)

If the 351 has a throttle body and EGR, I'd suggest removing each and examining them. EGR valves often get clogged with carbon, causing odd things to happen. The throttle bodies (especially on the 5.0s) are notorious for mechanical wear causing erratic throttle control problems. On my '88 F150, the throttle plate shaft area was worn and the throttle would stick in odd places. Also, the idle bypass liked to get carboned up and not work well. IIRC, the throttle bodies were unrepairable throwaways (unless one has significant mechanical and metal-working abilities).

N