I have a 2004 Jaguar XJR-S with 49,000 miles. When the car is cold I'm noticing that it runs rough when traveling at a steady speed. The tachometer will dance up and down between one to two thousand RPMs and the ride feels noticeably jerky, like power is fluctuating to the drivetrain. Once the car warms up fully the car rides like it should. Is this normal? I'm also noticing that, warm or cold, the transmission wants to shift out of first to second immediately. This shift is not at all smooth. Two separate issues I would think. Would appreciate your thoughts and if anyone has experienced similar problems what solution worked for you.

My first post to a forum. Hopefully I'm not making a newbie mistake. I tried searching the forum for posts by someone with similar issues but was unsuccessful.

Thanks in advance for your time.

 

what you describe seems like transmission surge its a well known problem and has a Technical Bulletin for it-- think it involves a reflash of the TCM. every likliehood the other issue is transmission also: so your best bet may be a trans flush and reflash.
I get the surge on my xj6 in 5th and 6th usually around 50mph and rev counter moves from 1600 up to 1900 back and forth if I take it above 65 it goes away and fades once trans is warmed up.
The jump 1-2nd is also well documented again could be fixed by new trans oil, filter and adaption.