Morning. I am new on here and needing some help!! I have a 1995 x300 sovereign which has a very annoying fault. When driven from cold the car drives beautifully but once driven for an hour or so and then shut off when I go back to restart the car it idles very rough and then stalls. If left for a cool down period (couple of hours or so) it then starts fine and runs great!! I have been given many suggestions such as the cam position sensor losing signal or the crank position sensor being at fault. Could any of you narrow down the possibilities of what is causing this??

 

The usual issues are poor starting and misfiring from cold where the CPS or CKPS are regular culprits.

You have the opposite problem where the misfiring is with a warm or hot engine. My first thoughts are the ECTS (Engine Coolant temperature Sensor) could be sending an incorrect signal to the ECM which then sets the conditions for a cold start.

Diagnostic Trouble Codes are always better than theory or guesswork!

Graham

 

Thanks for the advice! You are the second person to mention engine temp sensor, I would never of looked in that direction
As you say, diagnostics is the next step. Are there any particular codes I should be looking for?

 

The ECT sensor error codes are P0116, P0117, P0118 and P0125 but the best approach is to have the codes read and post them here.

Graham

 

Thanks Graham,
Will investigate and come back with the findings!!

 

I am extremely lucky that I found out what problems faulty ignition coil packs will cause before I spent money on other things like fuel filters and pumps,CPS,ECU issues,TPS and transmission diagnosis. I simply replaced the coil packs in my Jag and she has been purring along ever since.
Before I replaced my bad coil packs my car was acting absolutely crazy. Idling high,low shutting off at any given moment,dash lights flashing like a Christmas tree, transmission limp mode light coming and going. Even the airbag indicator would illuminate.
The new coils solved all those issues. My car has been running perfect for 23,000 miles. If it acts up again I'm going to just replace all the coils before I do anything else.

PS
I replaced all of mine with 2000-2006 Lincoln LS V8 coils for $8.50 each. They have proved reliable enough for me. So far 23,000 miles.
I would hate for you to spend the time and money chasing all the those other symptoms when you only have bad coil packs.