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.

 

alex ,the very best thing you can do is upgrade your management,injectors and loom on a cossie .all that old wiring and old management won't do you any favours ..

my first port of call would be the engine multiplugs on the cowl at the back of the engine .pull them apart and clean the connectors.

 

Is the boost maybe to high?
Are the coorect plugs mounted with correct cap?
Are all houses correct monted and tight?
Are the ignition timing correct adjusted?
Test Sensors for ACT, ECT, Phase. Do they work correct and connectors are dry?