I've recently finished building my car back up but am having slight problems. Basically it started misfiring at high loads, cutting out completely when hot and seemed to lean out badly when going downhill if I took my foot off the throttle.
The car has had a group A coil, new leads, plugs, dizzy cap and rota arm so it cant be a spark problem.
The fuel pump was also replaced for a Focus WRC pump thats a higher output than a Bosch 044 so its not the pump.

What I'm wondering is could it be the fuel accumulator causing this which I desided to keep when I went to MFI? I was told to keep it as it helps stop fuel surge etc but can they fail and cause these sorts of problems?