So you're saying "weak spark"....exactly how have you determined this ? With a proper scope/ignition tester, or some sort of spark jumper ? other ?

Have you confirmed the signal to the coils is sound ? Scope current getting pulled for each cylinder pair ?


You could try swapping the leads for 4 and it's firing pair to see if the problem moves to other cylinder, which would be 3 and 4 to see if problem moves to cyl 3

https://talkford.com/community/topic...ht-lead-setup/

Faulty ecu's are usually the least likely cause...perhaps even more so on a wasted spark setup that is firing sparks 2 cylinders at the same time...yet you're saying only 1 cylinder is dead. That doesn't make sense.