X type engine failure
 

2003 x type 2.5L Intermittent engine failure. Engine abruptly turns off. No notice, no stuttering. Will restart after 30-40 min. (sometimes longer). Runs perfectly until next stop, 20-100 miles. Repeats. Dealer can't diagnose because engine runs in shop. Any history or ideas on trouble shooting this type of problem?

No CEL?

I am out of my knowledge area on X Types but on the XJ/XK I would check the power relays to the ECM and the connectors on the throttle body.

I don't have a solution to your problem, but I have removed your email address, it is not wise to post it on an open forum.

J Solters, normally with the X-Types, a problem like this is associated with the fuel pump. A check that you can do is to get the car to fail. Then, cycle the key to the OFF position and then back to the RUN position (do not attempt to start the car). You want to be near the rear passenger door with your head semi under the car. What you are listening for is the sound of a running pump. This would be the fuel pump. No noise, fuel pump is not working. The more accurate way is to use a fuel pressure gauge. There is a schrader valve inside the engine bay that you would need to connect up to. Then you are looking for the fuel pressure to rise to about 50 psi with the key in the RUN position and the engine not running. But, short of running around with a gauge in your car just because, the easier check is the hearing method.

From there, we can narrow things down for you.