I have a 2000 XJR with 80,000 miles and my cruise control just stopped working. The driver window and sunroof just went through a series of battery resets, but now work fine. Apparently a computer malfunction/bad code. But the battery reset hasn't got the cruise control working again. And I am getting no computer codes, although I just had the intake gaskets replaced, and the car was on restricted performance. Does the cruise control not operate on restricted performance? What do I check next? Looking for clues for troubleshooting a inoperable cruise control

 

Haven't noticed, but I'll check to see if the tail/brake lights are working. That would be too easy! I just spent $1400 having all the intake manifold gaskets and vacuum lines, plugs, etc replaced, so the restricted performance came off. I have a computer code reader that can clear the codes, so I assume that it should clear the restricted performance. But about three days later after the shop work, I went on the highway for the first time and I got tremendous hesitation or staling under any heavy accceleration again. Restricted performance came back on about 60 miles down the road, although there was no missing, just no passing/heavy acceleration. I checked for the code, but all I got wa err. So I cleared it again. So now I'll wait for another code to come up. Gas mileage on the highway is only about 17-18 mpg. Is that average for a XJR? And on A 2000 XJR with 80,000 miles, when do I think about timing chains? Does this model have any timing chain issues? Thanks for any suggestions