Have another post here on this problem but I’m not real familiar with the ins and outs of the electrical system. Have misfires on cylinders 3 & 4 and high voltage to an O2 sensor, swapped it coil packs same codes, put new plugs in, same codes. Did recently replace vapor canister and alternator.

could the vapor canister cause the misfires? It ran better but a little rough after new installation then after about half a tank of gas lost power.

Thank you.

I think it’s going, not sure if codes messed up or I messed up but I checked the coils redneck style and pulled the coils while the engine was running to see which cylinders were dead then swapped and did it again, the dead cylinders followed so I put two new coil packs in and it seems to be working.