Random Misfire Codes

[Monty in Calgary]

A mechanic buddy replaced all spark plugs, all plug wires, and coil pack.

Started getting multiple misfire codes about 2 weeks ago. RANDOM, particular cylinders (4,5,6), Misfires on Startup. Code reader says Severity 2 out of 3.

Mechanic buddy figured faulty coilpack. Took out the cheaper coil pack and replaced it with an OEM one.

Drove the truck a few times for two days. No codes. "Felt" like it was running fine. TODAY, however, all those same codes showed up again. Had the code reader in the truck. Recorded and then cleared the codes, drove home, no new codes.

Any ideas? I'm at a loss as to how to diagnose this.

 

[franklin2]

Did he gap the plugs or just stick them in? If the gap is a little wide it will cause a misfire. You can also take each wire off and take a ohmmeter and check them. They are fairly delicate and easy to pull the terminals out of the ends. It's just some cord with graphite stuff in the cord to carry the spark.

 

[Monty in Calgary]

Thank you. I'll check in to that stuff.