Did you notice whether the tacho needle moved when the engine was cranking but not starting?
If no movement then it points to crank sensor (or wiring, or connectors or input to the ECU)
If it moved then I would take a closer look at the fuel pump (and relay if there is one)
No, I did not notice the tacho needle move, and I
think I would have had it done so. The fact that changing the crank sensor cured the fault strongly suggests the fault lies there. On Friday the car died after two stalls 10 miles from home. After half an hour it restarted, and got me home, though tried to stall once. This morning car would not start, or show any sign of doing so. I changed the crank sensor and it started straight away. I tried a couple of restarts, OK. I drove it to Bristol, parked, shopped, restarted car and drove home. 30 miles in all, no failures to start, no stalling.
Failure of the new Vx sensor seems most likely explanation. How do I prove it?
I may still have the original failed sensor. I could compare it electrically with my new Vx sensor and the pattern sensor. That might be enlightening.
I could replace the pattern with the Vx and see if it runs. If it does, then car wiring is suspect. If not, Vx sensor must be guilty party.
Do you agree? Have you any other suggestions? If it runs all week on pattern sensor, but will not run on Vx sensor, I could invite the dealer to change it and witness the failure.
Are not these Omegas bundles of fun? Meanwhile wife's 2.0 estate needs new lambda sensor and the 3.2 needs a new clutch. I shall never get bored,