cylinder 2 and 4
i replaced my lim gaskets and the 2 coolant elbows about 2 days ago. everything went pretty smooth, got everything put back together. but now i have a problem. its not leaking antifreeze anymore, but there is a misfire condition. there is also a weird noise when you first start it up. i got the ses light scanned. came back with codes p0420, and p0300. this happened right after the gaskets were replaced.
we had the ignition control module checked along with all 3 coil packs, they all checked fine.
the reason i think its cylinder 2 and 4: with the car running we pulled each wire from the coil packs. there was a noticeable misfire on every coil except 2 and 4. were checking to see if the fuel injectors are firing today with a noid light. now that should tell us if they are firing, but that wouldnt necessarily tell us if they are bad. we haven't looked at the plugs yet either. any suggestions on what else we should check?