I have changed plugs, coil packs, fuel filter, had inlet cleaned and runner flaps removed to see if it was any of them, nope no joy. Tried priming the lpfp a few times also, no joy.
I know what you are saying with regards to not doing it was it's been run. It will start perfect if it hasn't been sat for 7+ hours.
To me it seems like a fuel pressure dropping issue, since it's only really apparent after long stands