Help!!!

Ok i got a 97 Xj 4.0 5-spd...just bought it, the dealer said it was in exc. running condition...well heres whats happening, and i cant figure out whats wrong...ill b driving along and all of a sudden it will start running like shit, and then it will die...then after about 20 mins of sitting it will start up run about 100 yards and die again...then after getting it goin it will run fine...then about 2 hrs later it will do it again..

I need help like ASAP

Thanks
Brad

I would take (or tow) it back to the dealer who sold it to you and demand that they fix it. On a 97 they should be able to pull a diagnostic code from the PCM and find the problem almost instantly, but at a guess, it sounds like a CPS failure (crankshaft position sensor).

well i tried to code the computer...but it just pulled 12 and 55 (means nothing)...the check engine light dont come on or anything

Take that safety issue back to the dealer that sold it to you - duplicating it on the freeway in front of an 80,000 pound Kenworth could very well be the last thing you do. They may try the "as-is, no warranty" tale but that's BS...I successfully fought that with a dealer in Denver when the Vehicle Speed Sensor crapped out shortly after purchase (incorrect indicated speed, intermittent cruise control, etc)