I'm new here on Jag. Forum; I have a 2004 X-Type 3.0L (This is my third); It lost speed and have thumping sound under hard acceleration, if I eased off it slowly gain the speed again, it also happen when up hill. Engine idle quietly and rev up smoothly in park. I turned cruise on the highway @ 70/mh the car ran good for few minutes then start shutter and lost speed, one time the engine shut off, I almost got rear end by another car. Any body know what the problems, please give me some ideas how to fix it. Thank you.

 

The engine shut off happened to me once. I was on the interstate doing 70 mph or so and the rear wheels started to thumping and the engine cut out. I managed to get to the breakdown lane safely. I shut the key off and took it out of the ignition waited about 5 minutes put the key back in and it started up and ran fine and the incident never happened again. What caused it I do not know and it never happened again and this was over a year ago. Sorry this is all I can tell you.

 

your car went into LIMP MODE and probably set a CEL code. Have it read so you know where to start,(no parts yet). If it was severe enough it set a hard code if not a lite. Could be a multitude of things: fuel pressure, vacuum leak,bad misfire from any component.Need the code!

 

Here what happen to my X-Type after the post of its problems: Thought it my have not enough fluid, I opened the hex fill nut on top of transmission and filled in one bottle of fluid, it was run OK for about 35-40 miles then the problem started again, I bought and filled in a stop leak and prevent slippage fluid, it ran much better but only 60-70 miles it only stutter going up hill but not lose speed nor shut engine off, I poured another bottle of stop leak in trans. and it been ran so good until now over 400 miles, not even have the humming sound it used to have. Just want to let all the X-Typers know if you have same problems so you can try.

 

Thanks for the update!

I'm terrified of stop leak products, but I am glad it worked out for you. Have fun!