Just found out something interesting - as part of diagnosing the leaking injector problem I was told to pull the fuel pump relay or fuse at idle until the car stalls - then leave it for however long it would normally take to play up - and reinstall fuse and try and start the car and see if the problem remained.
Now, on the weekend I replaced the fuel filter - and to de-pressurise the fuel system you do the same thing. However - when I was doing it in the weekend, it would take up to sometimes 20 seconds for the car to splutter out and stall after removing the relay. The car was pretty cold when we did this.
Just now, after about a 15 minute motorway drive followed by a 5 minute urban drive, the car was nice and hot and pulling the fuel pump fuse it'll die within a few seconds.
How come it took so long for the car to die when it's cold, yet only a few seconds when it's hot?
Am I looking at a dying fuel pump, not giving enough pressure?
Or perhaps a bad fuel pressure regulator that doesn't hold pressure when it's hot?