Random coil on plug failures

[Shawn]

2006 Nissan Pathfinder SE 4.0L V6

First off this is not my vehicle and helping my buddy fixing the issue he is having. It all started when 2 coils that failed. He drove it back home misfiring who knows how far and parked it. I scanned it and 2 cylinders were misfiring(don’t remember which ones) and also P0420. We’ve replaced the 2 coils, all new spark plugs and was good except the P0420. Catalytic converter was not replaced yet since he could not afford it at the time. Drove for a week and another coil failed. Replaced that and all was good. As weeks went by random coils were failing. Now all coils have been replaced with new ones and still new ones have failed. I don’t know how to describe it but the oem coil on plugs were warped on top as if it was too hot. We determined it could be a possible bad ground and made sure all ground connections have good contact but still failures. Later on notice lack of power on hwy and pinging and possible knock under acceleration and threw a code that flashes when it senses the pinging. I forgot what code it was. I think the converter is clogged? High exhaust gas back pressure? Can this cause foul spark plugs from burned gas not being able to go anywhere shorting the coils? I am lost and hoping someone can help rather than dealing with repair shops. I know P0420 should have been addressed but can this cause random coil on plug failures? I like to educate myself on diy auto repair. Flamers can flame on and as we all know we all start somewhere.

Thanks guys
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[college man]

Are you using OE ignition coils or aftermarket? If you do have high
back pressure your not getting rid of the fuel air which will make
combustion temps go up and your timing is going to try and correct
for detonation.

[Shawn]

Coils are aftermarket from Oreilly. Just talked to my buddy and so far 5 new coils have been replaced within the past 4-5 months. As of now the SUV is missfiring again. I will scan and check to see what code comes up.

[college man]

These nissans are picky with ignition parts and electrical parts as they
don’t work well with aftermarket with that said If your exhaust is restricted
your filling the cylinders with fuel and not lighting it. which will kill the
ignition system and clog/melt the cat. Try removing the front o2 and see if
the back pressure goes down.

[Shawn]

I will have to try and hunt down some good used oem coils as they are quite pricey new. What about the Import direct coils which says ” actual oe part ” from Oreilly. I have purchased a set before for a Mazda and they seem to be working fine as the oe has failed. Maybe Nissan is just picky.

[college man]

In my experience Nissan Only. Believe me I have tried it and waste
my money and end up getting the OE stuff anyway.

[Author]

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