DOES ANYBODY KNOW WHAT CAUSES THE ENGINE TO SUDDENLY SURGE FOR NO REASON WHEN YOU TAKE YOUR FOOT OF THE GAS ,IT IS A INTERMITTEN PROBLEM,HAPPENS A FEW TIMES PER MONTH,KIND OF SCARRY WHEN COMING TO A STOP,I HAVE DISMANTLED THE CRUISE BELLOWS SINCE THE CABLE WAS CUT ANYWAY,I REMEMBER A COURT CASE A FEW YEARS AGO ABOUT A SIMILAR PROBLEM,BUT JAGUAR SAID THE KNEW OF NO SUCH PROBLEM WITH THE V12.IT SEEMS LIKE THE GAS PEDAL TAKES ON A MIND OF ITS OWN.THE AIR VALVE FOR THE IDLE IS NO FUNCTIONING AT THE MOMMENT,RUNS AT FAST IDLE 1200,COULD THIS BE THE PROB?IF SO WHY INTERMITTENLY?

CHEERS KEV

Submitted by arsenaultd@ear… on Wed, 04/13/2005 - 01:20

It would be helpful to know which year XJ12 you are referring to. The 1994s have an open recall for sagging hood liners which can ( according to the recall) interfere with the throttle tower operation and cause surging or sticking throttle. Probably does not apply to Series II XJ12s

Daniel Arsenault
Lakewood, CA
1994 XJ12 Morocco Red
1995 XJS 4.0 Rose Bronze

Submitted by grahamdallen@aol.com on Tue, 04/12/2005 - 17:08

A quick test would be to disconnect the air temp sensor fitted on the left hand air filter intake. Make sure the throttle butterflys are set to the correct air gap and both are opening together. Be sure to get the idle valve sorted too. Regards