Misfire investigation (in part)

[SwolebaFett]

21 JTR, second engine, 50k kms.
Had the code PO305. Misfire in cylinder 5 but didn’t store the code and was told to monitor it.

The first sign I thought something wasn’t quite right before it misfired was some engine fluttering at 6500RPM, full throttle going up an incline. First thought I had was maybe spark plugs?? Then after some time the fluttering caused a flashing engine light and engine vibration and a P0305 code. Engine light self healed and engine runs great and nice and quiet.

I figured today I’d pull the #5 coil and plug and this is the plug. It smells like oil but it isn’t wet. I had a new plug to replace it with. Any thoughts as to the condition of the plug?

Did changing the plug fix the issue? I’m having the same misfire in cylinder 5 right now.

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[Maximus Gladius]

Did changing the plug fix the issue? I’m having the same misfire in cylinder 5 right now.

Yes it did. I did an Ohm test on the spark plugs. The bad #5 plug read 5 Ohms. The other 6 plugs read Ohms of 6-8.

With a multimeter, set to Ohms, one lead to the bottom of the plug and the other lead to the very end of the iridium tip.

 

[SwolebaFett]

Thanks, yeah I moved the spark plugs 5 & 3 to see if that would change anything but it didn’t work. So now I switch ignition coils around for same cylinders to see if that’ll work.

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