If that don't do it look for manifold air leaks. First time I lost a cylinder with this new build it was a leak on the front cylinder. At idle she was missing bad once I was heading down the road with more throttle she wasn't bad. Last time I lost a cylinder just before I tore it down for paint it was coil related. I limped it home shut it down and that was it she would not fire on either. She did not run again until after paint and a new coil.