I searched with no luck so I decided to go ahead and ask the question. As the title states, When on the highway(about 60 to 80 MPH) it all of a sudden jerks and feels like it bogs and right after the RPM's go up then come back down. I seems to me like there's some slippage of the tranny(hence the RPM's going up). Any thoughts on what could be causing this? Its seems to be getting worst. I plan on a filter and oil change as soon as the weather permits, well see what happens after that. Thank you for any help.

 

i only drive sticks but wouldn't a slippage only occur during a gear change?

 

It doesnt seem to slip while its shifting gears, it only does it at higher speeds. By the way, the tranny is an aw4.

 

Anyone have any suggestions on what could be causing my XJ to buck and jerk like that? I really need to get this fixed before it gets worst(which it seems to be doing it more). Thanks for any help.

 

Hard to tell from your description, but if it is the transmission/tcc failing it will continue to get worse. Best advise is to take it to a trusted transmission shop & see what they say before it strands you.

 

On a different thread someone mention a similar symptom and mentioned it was related to the TPS, but it was for an older XJ so Im not sure it would apply to my 01.

 

Yes I'd check your TPS. The sensor itself as well as the cable coming out of that linkage on the side.

At highway speeds you're right, it shouldn't really slip in the way that you'd get with a fluid problem as the torque converter should be locked.

 

Ill check the TPS. What cable are you talking about? The TV cable that goes down to the tranny? Also, I recall reading somewhere on the forum that the TPS on these XJ is not adjustable is this correct? Thanks to all for the replies.

 

TV cable indeed. Yeah, the TPS isn't adjustable past the Renix era. But the sensor itself can go bad. Electronically it's the same thing as a volume **** you'd find on an older stereo. You know how when they get bad/dirty they crackle and pop? Same thing. Pretend volume corresponds to how much the computer thinks the throttle is open. Best way to check it is with an analog multimeter. There are a few writeups around here on what you want to look for.

 

Not sure if its what your getting but i had that issue and it was actually a bad spark plug. I changed all my plugs, problem fixed.

 

I recently changed all spark plugs with Champion coppers. Unless I got a bad one but it actually was doing it before the spark plug change. The thing that puzzles me is that Im not getting a code(besides the p0455 which I need to take care of too).

 

I checked the price for the TPS and it's $51.99 @ O'reilly and $94 @ the dealer. If I do need to buy one, what do you guys recommend, dealer or O'reilly(which carries a life time warranty)?

 

Does it seem like it's down shifting? I had a problem where mine would shift in and out of OD, adjusted the TV cable and it's been fine ever since.

 

No it doesn't feel like its down shifting. It feels more like its slipping. RPM's go up and come right back down. I already tried adjusting the TV cable once but it wont hurt to try it again. Im gonna try the filter change next weekend and if thet doesnt work Im gonna check the TPS or maybe just replace it.

 

Mine was obviously shifting in and out of OD. TPS seems like the place to start in your case.