New here. Not sure if this is in the right place or not, if not I apologize. Anyway, my brother owned a 02 Grand am gt with the 3.4, he first got it a year ago, & it ran rough. Wasn't taken care of, never did tune ups. I had to do intake gaskets for him, (he doesn't know about cars) so I told him to be safe do head gaskets also. So he bought them, I did those while it was apart, since then He's drove it fine, ran smooth. But he still didn't take care of it, I just bought it a few days ago, & been going threw it fixing what needs to be, I'm having an issue with a p0306, misfire on #6, he said he had AutoZone check codes, & said something about to much fuel in the catalytic converter, Haven't seen that code yet, but I just put in 6 new iridium plugs, wires, also bought a coil pack. Still missing. Ran some tests, it's getting spark, I used a screwdriver & could faintly hear an injector pulse, couldn't hear if it was consistent or not. I was cold, it was snowing and I was rushing, so I'm getting fuel(I think), I'm getting spark, just curious, I checked the compression, it's good. Still missing. & The check engine light flashes at times. My question is, the icm(ignition control module). Could it possibly be bad only on that coil & not spark consistently at times? I'm lost. Igot it for free, but after putting a starter on, water pump, brakes, rotors, tires, coil, plugs, wires, radio, & misc stuff, I wanna be sure before I spent the 120$ for the icm, or if it's an injector & spending 100$ each, since I'd do all 6. I'm sure I'm missing things, but I tried keeping it short. Thanks in advance for your help!