I have a 1991 3.9l Dodge Dakota Auto 4x4 and yesterday I noticed when I started the truck the engine immediately reved up to 2500 RPM and slowly settled down within 4 or 5 seconds down to the proper "normal" idle. It hasn't done this before. Ive had a lot of problems with this truck in the recent past. In one situation I tested the TPS(which I believe may be the culprit right now causing this) and it tested with a meter as "OK". The truck Revs high when its started whether its a cold start or a hot start.

I have replaced the following in the past month or so:
* Idle Air/Speed Control motor(set the idle as I was suppose to per the Haynes manual)
* Coil, Plugs, Wires, Pickup, Entire Distributor, ASD relays, Clutch Fan relay
* Water pump/hoses/thermostat
* Coolant temp sensor
* Cleaned the Throttle body
* Replaced the fuel filter and have ran at least 5 full tanks with Sea Foam treatment threw the truck
* Checked throttle body gaskets(appear to be ok)
* Checked for vacuum leaks, none found.
* EGR is bad and has been disconnected and the vacuum line serving it plugged.

Any input would be appreciated, Thanks in advance!