Cannot move my xj8. Starts right up, won't shirt. What to do? Any suggestion appreciated.

There are many simple tricks and items that can cause this. Does shifter move?
Wiggle steering wheel.
Check shifter cable on side of transmission
Brake light switch failure.
There is button to unlock shifter, never used it, many know it to get cars in neutral.

Read this thread. https://www.jaguarforums.com/forum/x...k-85682/page2/ There is a wingnut that will release the shifter and items to perform in order to isolate the true cause. Or watch this video:

Look under the car to see if anything has dropped off. There is a known issue in the past regarding the shift linkage coming loose and a couple of nuts (or bolts?) falling off and sometimes even being under the vehicle. I recently had a problem where my shifter was unable to go into park and then unable to shift out of park. The vinyl sealing strip inside the console that kind of seals around the shift lever is breaking up and a small piece was sticking out enough to catch the lever and prevent it from moving. Not always nor the same when it happened but after panic in the parking lot where I couldn't move the shifter into park to shut off the car I found the problem. Good luck.

Bolts. 8mm hex head.