I have recently bought a Cosworth. has a misfire that comes on when going to full throttle.

- swapped plugs and wires and new rotor as well which made it a bit better but still has a problem.
- at part/slight throttle it seems fine/better but as soon as you give it more than 50% it breaks up.
- wondering where to look next. plugs where very sooty and it was difficult to start as well.

any pointers would be greatly appreciated.

Cheers.