tranny vs misfire vs other

ok so i have a 99 xj sport 140k and im not sure if the trany is slipping or shes misfiring or i have a vacume leak or maybe a bad sensor

ok well i first notced that the rpms kinda jump its slight but it doesnt stay steady when idling, than when i am going it kinda feels like the trany is slipping but it doesnt do it all the time seems to do it more up hills if i hit the passing gear it stops

help

ok after thought what tranny do i have its an auto.?

since it is an automatic you have the AW-4 tranny. All XJ's with the 4.0 (to my knowledge) were paired up with the AW-4. I don't know much at all about it than what i've read on here, and it's apparently one hell of a tough tranny.

I had the same symptoms. I thought for sure the torque converter or something was shot.

It was a misfire. It didn't throw a code until it had been doing it for about a month.

New plugs, wires, cap and rotor fixed the problem.

Try that first.

http://www.naxja.org/forum/showthread.php?t=49842
http://www.naxja.org/forum/showthread.php?t=59924

ive heard that aw-4 can go 400k with out any major problems