I do have a question. When the car is cold and I drive off, the engine surges about 100 to 200rpm's between 1100 and 1700ish depending on the speed limit. It is pretty consistent until it warms up. It often causes the trans to shift up and back down. It has occurred to me that it might be the other way around. The trans is not warm and is shifting irregularly causing the motor fluctuation. Anyone else experience this? I have 51k on the car. Thanks for your help!!

 

If it has the ZF 6HP26 auto box then that would be like the S-Type, where it's the TC not working quite right. Sometimes a reflash fixes it but mostly people live with it for years as changing the TC is not cheap.

 

2004 with 205,000
Mine does the same thing....
80mph bounces 2000 to 2100, 2200. When very cold, the colder it is the worse it is.
Can even feel it in the seat of the pants.

Been doing it for years..... I got the car with 40,000 miles in 2008.
I had the transmission serviced a couple years back, new fluid, filter AND a reflash of the software. No change.

live with it I guess....peculiar to Jaguar?

Tom
2004 XJ8 205,000 miles, daily driver

 

If the issue goes away fully when the transmission warms up it's a software glitch. Well known issue on the S-type.

Not sure about a similar bulletin for the XJ.

 

Mine does, goes away. but only when FULLY warmed up, say 30 to 45 minutes...

Tom

 

TC, then. Expensive to change, seems to last for years if ignored...

 

It is the very well known "hunting" syndrome. I have it on authority from an ex-Jaguar man at my local indie, that this was deliberately put in to create friction in the torque converter to warm up the transmission fluid quickly. The hunting is the switching in and out of the lock-up. Once the fluid is warm the hunting disappears as the TCM turns it off. Obviously this got people cross but Jaguar could only fix it by changing the torque converters as new friction blocks on the lock-up were reprofiled so the hunting did not appear. Apparently the TCM software cannot be changed because it is part of the emissions control so illegal to change unless all the test are re-run, and we all know that ain't going to happen with a car out of production. So it is live with it, basically. I just put my car in to "4" for a few miles

 

Thank you for the thoughts and assistance. I guess we'll put in "4" and live with it!!

Thank you,

 

Thanks. This parallels and confirms several things I've seen and heard.

 

I've been having the same issue. Bought my 04 XJR with 40000 miles on it and it now has 93000 miles and has been doing it since day 1. No problems cause of it though. I just think of it as the kitty constantly wants out of her cage.

Regards
T B

 

You never notice it if you get onto a fast road or motorway straight away and cruise at 60 or greater !

 

Absolutely correct and for known reasons- the software glitch responsible for the surge only occurs between 40 and 60 mph.

From S-type TSB S307-14:

"This Technical Bulletin has been issued to address a customer concern of a surge in excess of 150rpm during engine warm up, at a temperature of 30°C to 50°C and at a vehicle speed in the region of 40mph (64.3kph) to 60mph (96.5kph)."