I've got a haunted 2002 Grand Cherokee Laredo 6 cylinder. I did some research on symptoms of a bad TPS and it matched my issues. I replaced it yesterday with a new part and the symptoms are still here. It will go just fine for a while, but at random no matter the speed, The RPMs jump above normal, and the mobility decreases a whole lot. It was crawling and I couldn't even make it up a slight hill. When I let off the gas while it's in drive, the engine shuts off and I have to restart it. When I restart it I can gun it and things will be fine again for a little while. It is a big problem as both of us driving it have nearly caused wrecks.
I don't know if this has anything to do with it, but the battery drains a lot and we have to jump it with a portable unit. Cold or not after driving around all day. The alternator seems fine, but the battery sucks. Maybe differences in power from the battery to the TPS? Any insight would help a lot. Thanks.

 

is the check engine light on? have you checked to be sure your alternator is charging?

 

Pull the battery out to see? Get it charged up fully.. Take it to someone, or somewhere who will put it on a slow overnight charge for you (if you do not have the means). After this, let it sit on it's own outside of the Jeep. Go back to it after the amount of time passes from when it would normally be drained, and check on wether or not it held voltage well while not having it connected to anything in the Jeep that may have been draining it?

While you are doing this with the battery. Find every ground on your Jeep, and clean them all up very well with cleaner and an abrasive. Pay particular attention to all of the main engine compartment grounds located on the chassis and the engine block, but get them all.

It sounds like it may possibly be related to having bad grounds, to me.. It probably is needing to be done anyway. It is difficult to chase, find, and to fix problems when the basics are not up to par. Such as the battery and grounds.