Strange Problem: Transmission/rpm

[ratpackman]

I have a 95 YJ with a 4cyl automatic, and when I am going around 45mph or higher and I am pressing hard on the gas my rpm's will actually drop and the engine seems to sort of lull down. If I ease up slightly the rpm's jump back up and the engine revs higher. There seems to be a problem with whatever it is that sends a message from my gas pedal to my transmission to shift up or down,and if I have the pedal sort of balanced in between, the rpm's shoot up and down erratically every few seconds. This is getting very annoying and it all started about the time I had the tranny and other things looked over by a Jeep dealership mechanic around the time my warranty was going to expire, just to be safe. The problem is I never got back to the shop to see what the mechanic may have mis-adjusted, and the dealership is now no longer Jeep. What do you think is causing this, and is it something I can adjust myself like linkage? Or is this something a shop would have to get into? Thanks.

[CanaMark]

Just because the dealership is no longer, doesn't mean your warranty is up. Sure you might as easily get things fixed, because the dealer you bought it from wants to please the customer and get their "ranking" up for customer satisfaction. But since you took it to a dealer and they messed it up, and ever since they worked on it its been running like crap. This is all evidence that its an ongoing problem and is still covered by warranty until it is fixed.

[fredjacksonsan]

I'd suspect the throttle position sensor first.