Chevrolet Repair: Engine surge, chevy s10, climbing a hill

Question
I have a 1994 Chevy S10 4.3L V6 2WD A/T engine vin W. It runs good when it is cold but as soon as it starts to warm up it has a surge.If you just barely crack open the throttle it surges about 150-200 rpm.It surges about 50-75 rpm between 1000-2500 rpm. Around 2000 to 2500 rpm it doesn't have much power,real flat when under a load like climbing a hill, unless you step down on it so the tranny shifts down to get the rpms up, then it takes off.I've checked the EGR,02 SENSOR,MAP,TPS. I've ran a scan and it says everything is normal. It idles at about 700-800 rpm. Any ideas? Thank you,John

Answer
THANK YOU! EVERYONE SEE ALL THAT INFO!!! THIS GUY IS GOOOD!!!!!!!!!!!
ok now to answer it..

have you checked the fluid levels?  and also it could  be a sensor sending faulty info to engine and angine thinks its under a load..hmmm   fuel injected? hmmm thinking.. im unsure at this point but could be a sensor telling the engine bad info and then revving it cahgnaes it... hmmm m boggled... i will look into it. but not much help right now,, sorry. e-mail me at renagade25sb@yahoo.com in a few days. i should have more info then..