Hi all
The revs on my Jaguar XJS V12 goes, from time to time, up and down.
Also, while driving, it suddenly goes down to max 1500 revs. If I try to speed it up it just goes up and down.
And as suddenly it came problems goes away......annoying...
Has anybody a good idea where to look? Ignitions look ok, fuel regulators are ok, fuel pressure not checked..
Could the Throttle potentiometer switch be the crook?
Soren
Denmark

 

Soren,

Your XJS questions will be best answered in the XJS Section, next one down.

Yes, there are XJ12 cars, but they are few and far between.

At the top of that section is a "stickie" that I wrote long ago about NO running V12's, BUT, much of that is the basic check list for problematic V12's also.

The TPS may well be a problem, as could teh fuel filter, the Ignition system, fuel quality, spark plugs, AAV is HIGH on my list also.

A systematic approach, ONE item at a time, will sort it.

Some of these might also help.

AAV rebuild procedure.pdf

HE Tune up.doc

SETTING THE THROTTLE CAPSTAN AND RODS GRANT.doc