Nissan Frontier: why is coil on cylinder 1 different looking?

the car is 7 years old, 30K miles, according to the mechanic there is a misfire,
the mechanic asked me if someone else had worked on the cylinder 1 before, because the coil for this cylinder.plug appears to be a generic one, does not look like the original.
The car had never had any issues and therefore no repairs. In the picture the coil in question is circled. He also wondered if the
issue is caused by bad gas. I drive 60 miles or less once a week.The engine
light came on once, for less than a minute when I first noticed a difference
in performance. I forgot to ask for the code.coil frontier 1

I called back for the code and was told that no code showed up. As I understand
his diagnostic tool using special cases then told him that the issue is with cylinder 1. The picture was sent taken by the mechanic.

If the coil look different, it clearly has been replaced with a one that is not a Nissan coil.

Why do you doubt your mechanic?

So the truck is 7 years old but you never say if you are the original owner.

Since you aren’t asking how to fix it or what is wrong with it, and you have a mechanic, the codes aren’t really needed.

I’m the original owner, the title lists an odometer reading of 7miles.
The coil and plug will be replaced.
Mechanic and I are baffled why there is a generic coil? What could be the reason?

You are really making us play “20 questions” here since there are 2 engines available for what I can only guess is a 2014 Nissan Frontier (you didn’t say, only that it is 7 years old) and it might be a 4 cylinder (again, you don’t say…but based on the connector position, it is a 4),
the NGK coil AND the Delphi coil on Rockauto both look exactly like the picture of the one in question. AND I also notice you haven’t posted a picture of one of the other coils for comparison…

I’d say there are 3 possibilities…

  1. There are 2 vendors to Nissan for coils and your engine just happened to get one different one…
  2. The truck was serviced at the dealer in the 7 miles before you bought it because there was a problem at pre-delivery inspection and the replacement coil was the 2nd vendor’s product
  3. Someone sneaked under the hood of your truck and swapped the coil out for a generic knock-off coil of indeterminate origin just to mess with you…

My favorite is #1. You can pick yours.


Why does #3 spark plug wire on my truck have a grey boot at the spark plug when the rest are black ?

On my neighbors identical truck, his grey boot is on #5

They’re the original wires on both trucks.

yes, 2014
it is a 4 cylinder
the car is at the garage, I can only use the picture the mechanic sent,
in the square you see a coil he identifies as original and it faintly shows a stamped number, the mechanic is the one who thinks they should all look the same, thanks for your inputcoil frontier 2

If you look closer at the picture, you’ll see that one coil is facing left and the other is facing right.

No reason to put the part number on both sides of the coil.


ok, my comments are based on the conversation with the mechanic and
his reasoning.

My guess is the same as Mustangman’s no. 2, the dealer you purchased the vehicle from noticed a misfire was occurring on that cylinder during a test drive, likely b/c the check engine light turned on, and changed the coil before you drove it away from the lot. It may be that the way that particular coil is mounted allows the coil to heat up a little more than the other 3. Or it might be the length of the wires that go to that coil are a different length than the others. Grounding differences could be involved too. I don’t see any service bulletins relating to that coil however.

That is the factory coil, there is an assembly line inspection mark on it, the part number is on the other side.

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This is the correct answer, and the fact that the mechanic did not immediately glom on to this makes me a little nervous as to how good the mechanic is…


possibilty 4:
the coil was turned around, the mechanic did not see that, but now that
I have looked under the hood, it is obvious, the installed coil was the original Nissan one. He replaced it with a new Nissan one and the spark plug. For cylinder 1 it looks like an easy exchange.

You can’t turn it around, it has one hold-down bolt, it only goes in one way.

you are right. The marking was on the other side and it was the original coil. Attached are the exchanged parts: spark plug, coil. The mechanic recognized that he was wrong when he claimed that the coil was not the original part… He has been a mechanic for 40 years and has worked on
my cars before, mainly maintenance work like brakes. He did not run a check
with his diagnostic computer after he exchanged the parts. Should he have
done it? He did a test drive. Is it possible that only the spark plug was bad and
caused the misfire? Or is it best to replace both?

Cost of the coil $148. Online pricing is much less.

If the miss is gone then… happy motoring.

Might have been nice. If he ran a check before he replaced anything, and it said cylinder 1 misfire, and then he replaced the cylinder 1 coilpack, it would have been a pretty good idea to then see if the misfire code was still being thrown.

But as @weekend-warrior said, if the misfire’s gone, drive on.

I paid for one diagnostic check. He said he has 40 years experience and can
tell how a car is driving.

The working end of the plug doesn’t look too bad, but hard to tell for sure w/the photo provided. The size of the spark plug gap is important too. The gap tends to widen with use, and the computer often boosts the voltage to the coil when that happens to compensate for the wider gap, which can eventually damage the coil.

Can you tell if this is a bad spark plug?

It looks ok to me. The gap seems wider than I’d expect to see, but I have older vehicles than yours. Maybe yours is supposed to be that wide. The two electrodes look like they are in pretty good condition. While the plug is removed good time to look for any tiny cracks in the white ceramic part too. Use a magnifying glass.