Weird noise and engine surge
 

I have a few issues with my MY2005 XKR.
1st. There is an engine surge at approx. 1400 - 1800 rpm. this seems to resolve itself after it has been driven some 20kms switched off and re driven after a short period (shopping etc).
2nd. Just over 12 mths ago code PO171 appeared then went away and never appeared again.
3rd. There is a noise in the rear of the car, this noise is best described as (A) an "oil caning" noise. (B) A "DOINK, doink" noise or. (C) a stretched body panel being pushed in, and it popping back out.
This noise started out only when the car came to a stop and was at rest for 30 -60 seconds. It then escalated to the car moving. Now it can occur when the car is stationary with the engine at a high idle to 2000rpm.
I have a sneaking suspicion all of the above are related and the noise is the fuel tank being vacuumed in and then released.
It's a bit hard to locate, as by the time I get out of the car and run to the rear, its to late to locate the source. A bit like checking your own stop lights.
Not familiar with this Jaguar. So has anyone come across this before or can make suggestions?
Thanks

Same car as mine, what a machine, puts a smile on your face every time the right foot goes down. I've had the noise from the rear too, I read the posts on fuel tank oil canning and went right through the vent system- couldn't fault it but couldn't discount it either.

Have a good look at the exhaust mounts on the rearmost silencers. The combustion heat expands the exhaust and you'll see a good 1/2 inch of shine on the pin when you look. I put some copper grease on the pin, noise has gone.

I had to fix that "Weard niose" in your thread title. It was driving me nuts! :icon_lol:

Another regular source of strange noises at the rear is worn "A" Frame bushes (RH arrowed in red):

Attachment 119618
(click on the image to enlarge it)

These metalastik bushes separate with age causing metallic noises on acceleration, breaking or just when revving the engine.

Graham

There have been lots of posts about deforming petrol tanks but never any conclusive proof. The NA cars probably have the full vapour recovery system so it's more complex than the UK versions. You can beat it though - don't lock the petrol cap into the bayonet and leave it so it is just sitting in the filler hole. The tank can vent and the noise should stop. Do this as a temporary measure to establish whether it is the tank. A more permanent solution is to drill a tiny hole in the petrol cap so it can vent and never collapse the tank --------->

Attachment 153570

Another source of a noise from the rear end is the parking brake. One my shoes inside the drum wasn't properly held by the spring loaded pin - so it was grabbing the drum and causing a clunk.

Thanks for the reply's to date, I get my machine back from the panel shop tomorrow (some arsehole slammed their door on the rear guard, (and it was the only car in the parking lot, and only there for 15 minutes). As my car is a UK import, I will try JIMFORRIST (uk) fix and see what happens. Next week I'll put it on the hoist and check the exhaust hangers and lube, and check the bushes as suggested. I'll let you all know how it went. Thanks Guys, I appreciate your input.

I think you'll then get code(s) for EVAP leak(s). (You do for sure on (non-UK, not tried UK) S-Types.)

If so, you'll have to make a proper fix...