Hi all,

My '05 V6 Coupe MT is running through ignition coils. I replaced all 6 coils and plugs with NGK replacements on 1/31/22. Coil on cyl 6 failed 2 months later, replaced under warranty. Coil on cyl 5 failed 1/9/23, replaced under warranty. And now the coil on cyl 1 has failed just last week. I'm trying to figure out why coils are dying so quickly, and I can't find any real reason. The failure is always happening/noticed on start-up, never after being driven for a while. Within 20-30 seconds of starting, the CEL will flash and I'm down a cylinder.
Anyone here have a guess as to what is happening here? I appreciate any input.

Thanks.

 

Do you still have the original coils? Had any of them caused misfire codes?

The coils are pretty simple, so there isn't much that can cause them to fail.

Here are some ideas as to the failures, but they aren't definitive.

It could be a bad batch of NGK coils, or possibly fakes.

Very worn spark plugs might cause the coils to fail.

Another thought is the dielectric grease. You only need the dielectric grease on the rubber boot to prevent sticking. Grease on the metal of the spark plug can prevent good contact.

 

Thanks for the response!

I don't have any of the original coils, I had to return them as part of the warranty claims, but they did cause misfire codes every time.

The spark plugs were changed with the coils in January of last year, and when I pulled them during troubleshooting they all looked fine. No excess grease, either.

I'm starting to think NGK had a bad batch and I'm just unlucky, but just trying to exhaust all of my resources before I finalize that conclusion. Are fakes a real issue? That thought never crossed my mind. I reached out to NGK directly to see if they will admit to having a bad batch, or if they'll do anything about this. It's getting old quickly.

 

I'm going through the same issue right now. 2004 Honda Accord 3.0L. I replaced all of the OEM coil packs in October with brand new NGKs from RockAuto. Over the last two months, I've already had to replace three of them due to failures. When I installed the NGKs, I also replaced all plugs with the NGK iridiums, and ensured the gaps were correct. I don't understand how I got 400K miles out of the OEM coil packs, and these NGKs are dying one after the other. I thought NGK was the way to go.

Now, RockAuto doesn't even list them as an option, so I also think there may have been an issue with them. I'm going to be reaching out to NGK and asking them to make good on them, and either replace or refund me the $200 I spent on the set.

By the way, the set I purchased on RockAuto were part number 48841. The ones at Advance Auto Parts are the same part number, but are a slightly different design, so there has definitely been a change in the product recently.

 

Apologies for the late reply. I never heard back from NGK after a couple messages, so it doesn't seem likely they'll help us for having wasted money on bad products. Did you have better luck?
I noticed the last NGK coil I received from Rockauto was slightly different than the ones that had gone bad before. They're now grey instead of black, and they actually felt a bit more solid.
I haven't had any issues in the past few months (knock on wood), so hopefully they're back on track.

 

Rock Auto replaced mine under warranty. Even though they no longer list the NGKs on their website, they still sent NGKs again, and they are the same design as the other ones that failed. I have the new ones installed, but haven't driven the car but a few miles since then (this is our spare car). BTW, I also had reached out to NGK before returning them to Rock Auto, asking if they've had any problems with them, especially since the ones at Rock Auto are different than the ones at Advance Auto Parts, but with the same part number, and they simply referred me back to Rock Auto for a warranty replacement (they did not elaborate on any issues). If I remember correctly, the ones at Advance Auto had a grey cap in the top center, but the ones from Rock Auto were solid black again. If these fail again, I'm going to order Hitachi coil packs the next time. Good luck with yours!