Jaguar 3.0 S-Type (2003)



The car surges (300-450 RPM) regularly at speeds of 30-55 MPH. The local Jag dealer would not hook it up to the diagnostic computer because (he said) it would endanger the computer and walked away. Any ideas, suggestions (not for the dealer–I’ve already thought of all those), etc?


Endanger the computer? How does this dealer stay in business if they can’t scan computers?



It isn’t the car’s computer that was “endangered,” but the dealer’s diagnostic computer. Unfortunately, I was not present during the situation; two men (a master mechanic and another car dealer) took the car over because they had never seen anything like it in their very extensive experience with automobiles. I guess the Jag dealer is still in business because no one has been able to tie him down on an ant bed and douse him with honey–but I digress.

What would you suggest? Would it do any good to call Jag’s American headquarters? My guy said he’d put in a new transmission if it got really awful to drive.



You’ve been talking to incapable people. An actual mechanic has included in his / her vocabulary a word: t-r-o-u-b-l-e-s-h-o-o-t-i-n-g. Those others can’t do it.
A mechanic would check all the things which have to do with engine operation; such as fuel pressure with the engine under load, ignition, vacuum, etc.
I would replace the fuel filter, and check the fuel pressure (at various engine loads), as a first step.
You’ll find a capable mechanic at an independent shop. Ask around.


Thanks–however it isn’t a power problem but a transmission problem.


How do they know it’s the tranmission if they won’t scan it? And I don’t believe that his scanner would be damaged just by reading the stored data. Find another mechanic that will scan it for you.


Thanks for your answer. The next nearest Jaguar dealer is half a state away so we’ll just see what happens.


Who, exactly, did you talk to? I’d find his boss, if possible, and complain. This is nonsense.


It’s the same basic car and engine as a Lincoln LS or Thunderbird…Try a Lincoln or Ford dealer…The scan connector is the same…


You say, the problem is in the transmission. Why do you think that? In the 30 - 55 mph range, it’s possible that the surges could be caused by the transmission torque converter SYSTEM. If the torque converter were locking, unlocking, locking, unlocking THAT could feel like acceleration surges.
The torque converter can be left unlocked, by pulling a fuse or relay, and then seeing if the surge is gone or still there. If gone, you’ve found the cause. If not, troubleshoot further.
A Jaguar isn’t such an exotic car that no one besides a Jag dealer can work on it. A local, independent repair shop, or transmission shop, would be a good place to go.


Sorry all, only just picked this one up.

Please check Jaguar service bulletin TSB S307-14.

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).

I’d start there, print the TSB out, stick it under your dealership service reps nose and hope he can read well enough to remediate his memory problem.