hi I have been having a problem were my A12 engine misfires only under load never at idle it more noticeable when yo get to 4000rpm it will misfire a few time.

I had this problem a few weeks ago so I reset the point dwell to around 50 degrees before this it would misfire really bad problem seemed to had gone but has reappeared.

i rechecked the plugs and points and all seems good I also tried a different (original) coil and does same thing.

Any ideas?

Thanks!