On my car, the problem turned out to be fuel starvation. The filter on the end of the fuel intake pipe in the petrol tank had fallen off- they found it lying in the bottom of the tank. So when I put my foot down, the sudden increase in suction would suck a passing piece of crud up against the pipe, blocking it. Then when the engine cut out, the suction would cease and the piece of crud would fall away again, allowing the engine to restart.
EDIT: This next paragraph was proven incorrect re: accessing the intake pipe and filter. It's still accurate if you ever need a tank strap changed though!
I'd advise taking it to the garage to get it sorted, rather than doing it yourself. So far as I know, you have to drop the fuel tank to get at the intake pipe and filter (no handy access hatch under the rear seat, hoooo no that'd be way too sensible). And to drop the tank, you have to drop the exhaust and its shielding. And the bolts that hold the tank strap onto the chassis? The nuts they screw up into (the ones built into the chassis) can come loose and spin, leaving you in a world of pain. I know this because it happened to the poor garageman I left it with!
Hope this helps.
PS The spluttering while cold and the cutting out immediately after a warm start are still present, so they're not related to fuel starvation.
"They might be drinkers, Robin, but they're people too"
- Batman, 1966
Last edited by Flangemonger; Nov 6th, 2009 at 11:59 PM.