I have an engine that is surging at approx. 1,500rpm with a very light throttle when cold (lean mixture) and a fuel tank that is noisy/"oil canning".
I have removed the fuel cap as suggested previously and this "fixes" the noisy tank.
I have checked for vacuum leaks and found none, and now removed the emission control unit from under the left front guard.
All hoses have been checked for blockages, none found. The elect switch checked for operation, OK.
The large canister checked for blockages. OK.
The small round cylinder P/n 1X43-9S446-BB is a bit if a worry, I can see through it, (through the pipe ends), it does not rattle or seem heavy, in other words its empty. (Now why would Jaguar use a useless empty cylinder?)
I had a look on Ebay and this part is described as a vacuum valve and priced at some 30UK Pd ($60 approx.). a lot of $ for an empty cyld.
Also I cannot work out how the fuel tank can pressurise/vacuum when the tank vent pipe connects to a "T" junction at the canister and the canister is vented under the guard.
Questions :- What does this plastic cylinder really do?
Is there a description of this and its use?
Why would the tank "oil can" with the above mentioned venting?
Is there a reference/diagram of the system?
Has anyone else had this problem and overcome it?
Cheers, Mike

 

This is from the 2003 shop manual - it's over my head but may help.

 

Sounds like trouble with the fuel tank vent valve on top of the tank. It's all described in the pdf that Clyons posted, in the section titled Operation of On-board Refuelling Vapor Recovery.

 

Thanks guys, The info from Clyons will help a bit, and as he indicates it is complicated.
It appears you need to be a tech wizard with a special machine that goes "Ping".
Thanks Astromorg, I'll have a look-see at the tank end.
Merry Christmas to all.
Mike