Originally Posted by
cj_rst
Is it definitely just on load? Can you make it 'misfire' when revving it on the spot? If you can then it could be valve bounce. In which case you want new valve springs. Seen this before on an RST engine and it seemed like it was only doing it under load but giving it a good rev in neutral produced the same 'miss'. Valve springs changed and it was sorted
sometimes does it when reving on the spot but only when you jus come back from running it, but my engine has only done 600 miles since full build so shouldnt be the valve springs surely, jus seems to me that its massivly rich on idle but no fuel on boost