Well i had a similiar prob on my saff cos last week it stated to miss bad, i had a spark on all 4 plugs, changed crank sensor still missed! I thought it was injector probs cause if i pulled of the connector on injectors 1&3 it made no difference to engine note, they were clicking thou so were working. A few days later i found it was the dizzy cap and rotar arm somehow putting a spark on plugs 1&3 at same time! Maybe it's all your prob is, hope it helps.