Just got the car, was running good for a day or so, then started missing. Code reader says misfire cylinder 3. Lots of misfires on the misfire counter. I started with , new plugs ( acdelco iridium) ac Delco wires, I've tried new coil, 3 different ignition modules, replaced fuel injectors, pulled valve cover and found nothing out of place, all valves appear to open the same ammount. Cleaned the ground under the ignition module also.
I don't usually ask for help, don't have to usually. I just don't know what else to do. Ive also cleaned the egr. Cleaned connection at computer, battery and ignition module plug. Even tried pure gas, no difference. And cat converter.
Any ideas?