I have had the engine, ignition and engine set-up.

But I am
1 having power loss when accelerating hard in 3rd or 4th gear at about 3000 rpm/70mph - this does not happen in 1st or second and I can accelerate very gently over a minute or so.

2 The engine will not start within 30 seconds of turning over when hot after being stood for several minutes.

This seems to be a fuel pressure issue The fuel is pumping at the engine fine and removing the fuel filter did not fix the issue.

Could this be a failed fuel return valve and what should the pressure be on the rail

Any thought/experience welcome.

Thanks Bryan 1971 S3

 

Check your fuel pump. V-12s have a dual sided pump and when one side fails you'll get low pressure and exactly the conditions you're describing. You can try cleaning the points on each side of the pump but the best solution is just to replace it with an updated version that has no points (but otherwise looks totally stock).