2000 Thor 4.6 fuel/starting problems

Can any of the collective knowledge on this group help with a fuel issue? I have a 2000 Thor engine 4.6. One day it just wouldn't fire up after parking up for a couple of hours, although turning over as normal. The AA guy checked all the relays, took a spark plug out (dry as a bone) and listened for the fuel pump. He couldn't get it going, but it tried on Easy Start. He could do no more and suspected the fuel pump. He was there for a good 45 mins and it just would not start. Whilst waiting for the tow truck I just thought I'd give it a go and it fired up straight away! Then died after a couple of minutes. It wouldn't start again until I waited another 45 mins or so. The same pattern happens. It fires up then dies after a couple of minutes. Does this sound like a fuel pump issue? A crankshaft position sensor issue or something else? It was running fine prior to not starting and runs fine whilst running before dying again. Thanks for any ideas! No warning signs on the dash either

Could be any number of things, including a dead fusebox. Need error codes read and live data views
Swap the relay with another of the same colour as a first start

Does sound like fuel relay or pump. Not sure if Thor has a fuel pressure test valve like GEMS, but if it does check the pressure.

Does the fuel pump cycle when the key is turned on?
Any weird noises from the pump if it runs?

Did some Bosch reading. Pump should run for a short while when ignition is turned on, but stops when ECU detects sufficient fuel pressure. Pump is then re-engaged when turning the engine over, and should remain running when engine starts.

So as others have said check relay is working. You could also try bridging the relay socket to see if the pump runs ok.

Also as suggested in your thread on the other forum, check the crank sensor.

Thanks all! Some good ideas here and further investigation by the garage is definitely required. I think thatbit is worth trying a new CPS first since that seems like a good place to start