1993 ford ranger rear wheel drive

hey all i hope you guys can help me out here.
my truck starts no problem but it revs over 2500 backdown around 350 rpm when i put it into drive or reverse it straightens out or even if i leave it run for a bit and if i rev it and let it go she goes all hay wire with the revs and back to normal and even when i have the cruise control on revs go hay wire there to, so far i replaced the mafs,tps and cleaned out idle air control valve and checked all my vacuum lines replaced wires and plugs gave the old tune up then some
and my fuel pump and regulator is workn just fine please help mee:banghead:
oh yeah its a 6 cyl

Any CEL (Check Engine Light) indication?

yes it was prior to replacing tps and tune up

Any possability of a vacuum leak at the manifold sucking in air? Same symptoms as my daughters car '99 1.8. Granted a totally different engine but the symptoms are similar.
If you get a 3' piece of garden hose put one end to your ear and move the other end around the sealing surface and listen for air......Mike

thnx i will try that and hope its the problem

theres no vacuum leaks compression is up in pistons and fuel pressure is up,everything checks out to be good she just dont wanna idle normal,befor she didnt keep a steady idle on the highway after tps was changed it does but idle is still messed

theres no vacuum leaks compression is up in pistons and fuel pressure is up,everything checks out to be good she just dont wanna idle normal,befor she didnt keep a steady idle on the highway after tps was changed it does but idle is still messed would it possibly be temperture sensor ?