p38 4.0 cuts out after 30 mins ???

hi, anyone had this fault before ???
car starts ok when cold and been lying a few days but after running for half hour it just dies, and when trying to restart it coughs and backfires as if timing is out, previously had tank pump diagnosed as having low pressure so dully had brand new tank pump fitted but still just the same problem , getting to stage of its going on ebay for spares or repair as cant seem to get to bottom of fault
any ideas or a fix would be appreciated

regards jim

Crank Position Sensor is / has shorted out ...

Probs due to "Warming" up when Cold Electrical Contacts are OK when it "Warms up" Contact is broken & Engine Dies Ect ...

Had A 4.2 Jag XJ6 with EXACTLY the same problem ...........New CPS GOOD AS NEW!!!!!!!!!!

what faults are in the ecu?