Hmm Well I just got my engine running.. and uhmm it sounds as if its missing? Ne ideas how to fix that? I have an aftermarket exaust on it.. I dont know what kind, it came with the car... lol but I think it makes no diff.. The piping is pritty much the same size.. But yes any clue? tips would be awsome>

ed Bello

 

air fuel could be off....or timing could be a smig off

 

What do you mean by it seems to be mis-firing? When you rev it up does it cutout?
Does it idle poorly, have loss of power, does it struggle to rev? rx7doctor

 

I know that this could seem like a relitively simple answer...but maybe your carb has carboned up and is injecting particles into the air/fuel mixture causing an impartial burn that could sound like a mis fire.