I just bought a 1990 xj6 base model jag a month ago. It has been stored for a couple of years but seems to be in amazing condition . It has 210000 km on it and has a couple of issues that I will need to address . The engine at idle makes a thumping sound .The previous owner said it always makes that noise and its not serious. I did a compression test and it shows 130 psi in all 6 so Im thinking valve rocker or lifter ? Also there is a vibration in the rear at around 40 miles an hour which increase with speed and goes away at 120 km hr. The tires are brand new so I know its not a tire issue. I bought this lovely vehicle as a project car and I will enjoy solving the problems and working on this . I am so happy that I discovered this forum and once again I thank you for letting me join .

 

Weclome Omega man! This is the X-Type are of the Jaguar Forum. You will want to repost your questions in the XJ6 forum. Scroll down a bit and you will finds it--I believe it is the XJ6 and XJ12 forum combined.

Good luck--you have found a great resource with great people here on the Jag forum!

 

IT will take a little practice. Thanks

 

Try leaving the transmition in 3rd gear to see if the vibration goes away.My 90 had a similar problem and it would not appear until the lock up torque converter locked up (converter will not lock up in 2 or 3). Finally traced the problem to a dirty and plugged up fuel rail an a bad injector and when changed every thing worked fine. Also make sure your catalic converters are flowing freely (ther are 4 of them).If plugged can cause a whole bunch of other problems (blown head gasket most common)

 

Thank you I will check these.