My truck starting missing on several cylinders a while back. First, I changed the plugs and upgraded the plug wires to 8mm. I still had misfires, so changed both ignition coils.

I took it for a test drive and it ran great for about 20 minutes. Once I stopped, shut off the engine, and started again, it ran horrible and I could barely make it home. By the time I got back, I had destroyed my cats (they were cherry red...I should have shut down and towed home).

I've now replaced the Y-pipe, both coils, plugs, and plug wires. I'm still showing P0733, P1590, P0300, 301, 304, 306, 307. Since those seem to correspond with the driver-side coil, I'm thinking I got a faulty coil. But when I test the resistance on that coil, it's within the proper range.

Anything else I can check? Could a cam or crank sensor cause misfires that align with all nodes in a coil pack? Could it be a faulty wire in the harness?

 

First check would be for resistance measurements on primary and secondary side.

 

Yeah, I checked the resistance on the coils are it's good. They are new, but I'm wondering if it's possible one could be bad and still show the proper resistance.

 

100% sure you have the wire configuration right?

 

Make sure the harness is firmly connected to the drivers side coil...obvious I know, but check the small stuff first.

 

Thanks guys. Yeah, I checked the harness before I removed them and the clip was on and firmly attached.

The wire configuration was my other thought: if a couple of the nodes were swapped, would it cause all of the plugs on that coil to misfire?

But I think I had it on there correctly.

 

If you definitely want to rule it out flip the coils. If the misfires follow you can be pretty certain that it's the issue. If they stay the same then you have some more poking around to do.

 

Im in the same boat. Just replaced my coils, spark plugs and ignition wires and still getting cylinder 1 missfire, flashing check engine light and red cat. Could bad ignition wires cause misfires? What else should I look for?

 

Couple things from experience.
1) It is super easy to mix up the wires in the coils.
2) pulling out wires from the coil, super easy to break the wire inside the connector.

I corrected a wire in the wrong hole, put in right hole, 6 months later misfire on that cylinder because the wire was fried. New set of wires fixed it.

Double/ triple check wire config. Plugs gapped to .040

 

Thanks, Ill order another set of wires and see if that changes anything.