FJ Cruisers of Northern California

2012 FJ - P0304 Code = Misfire on #4 cylinder

Hello everyone,

Need some help with CEL (Check Engine Light) and TRAK light coming on the FJ a couple days ago. 2012 FJ, 70k miles, daily driver.

CEL went on as I started the FJ in the morning. Put a code reader on it and it gave me a P0304 code which is a misfire on #4 cylinder. I was looking on the internet a bit to help me identify where the #4 cylinder is and I have come up with the following:

5 6

3 4

1 2

FRONT

Can someone confirm that I have the layout correct?

I pulled the Denso plug out of cylinder #4, tested on a multimeter and sure enough it appears that the plug is bad. Purchased a new Denso spark plug (same OEM), gapped it to .040 (within Toyota spec), applied anti-seize to threads, placed it in cylinder #4, replaced ignition coil, reconnected battery... started her up... cleared codes and CEL... ran about a minute then the CEL returned with a P0304 code.

-So #4 plug is good, coil is unknown, plug wires is unknown, fuel injectors are unknown.

I then disconnected the battery again... removed #4 ignition coil and swapped it with the #2 ignition coil... reconnected battery... cleared codes and CEL... ran about a minute then the CEL returned with the same P0304 code. Code did not return with a P0302 which would have meant the ignition coil was bad.

-So #4 plug is good, coil is good, plug wires unknown, fuel injectors are unknown.

Before I go back out and check on the plug wires...does anybody have any tips that might help me trouble shoot the plug wires? I'm pretty sure I can't replace a bad fuel injector myself and will need to send it a mechanic but, I want to eliminate the wires from the possible problems.

John

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Replies to This Discussion

Permalink Reply by DX FJC on December 7, 2014 at 6:36pm

This falls under the emissions warranty.

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Permalink Reply by Stormshadow on December 7, 2014 at 9:11pm

Thanks for the reply!

I'll try the dealer first in the morning but, I had thought the emissions warranty was only good till 50k.

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Permalink Reply by DX FJC on December 8, 2014 at 3:20pm

They were different for different years, but yours should be 100k. Cats, O2s, coil packs, injectors, ECMs, etc is all covered.

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Permalink Reply by Stormshadow on December 8, 2014 at 3:33pm

Thank you again... my FJ is at the dealer now. Will report back findings.

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Permalink Reply by Stormshadow on December 8, 2014 at 3:51pm

Well... that was... interesting.

Dealer just called back... yes, #4 cylinder is bad, coil is probably bad, and injector is probably bad.

Why?

Apparently, my engine bay was a nice home to some rodents and they chewed on cables pretty badly. Estimate is over $1000... dealer assures me that this type of damage should be covered by my insurance... Will call AAA now.

smdh.... rodents?!?!