Cylinder 8 Misfire

[Supreme_5.0]

Hey guys, so I’m having a cylinder 8 misfire CEL P0308. That’s the only code it’s throwing. I’ve read the other threads regarding P0308 along with P0300, but nothing I’ve seen about a fix for just P0308 by itself. Also haven’t seen anything regarding a fix for a gen3 coyote. Car has a rough idle and surges and hesitates while driving. I’ve changed spark plugs and fuel injectors to no avail. I have a 2019 Mustang GT FBO running E85 flex fuel tune tuned by Wengerd Performance. If anyone knows a fix or can point me in the right direction, it would be appreciated!!

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[Temovic55]

I would love to help making it easier but I myself need help as well lol
My car is still on revisions, it pulls like an animal except the hesitation/bucking which is real pain! while cruising.
I've had none of those symptoms when it was bone stock but since I went FI! It acted like a b!tch.
Anyways, if you're not running an open grille or having any sort of instability to the MAF sensor then I would suggest getting back to the tune! if you rolled out, vacuum leak, ..spark gap ..as well!

 

[Cobra Jet]

Hey guys, so I’m having a cylinder 8 misfire CEL P0308. That’s the only code it’s throwing. I’ve read the other threads regarding P0308 along with P0300, but nothing I’ve seen about a fix for just P0308 by itself. Also haven’t seen anything regarding a fix for a gen3 coyote. Car has a rough idle and surges and hesitates while driving. I’ve changed spark plugs and fuel injectors to no avail. I have a 2019 Mustang GT FBO running E85 flex fuel tune tuned by Wengerd Performance. If anyone knows a fix or can point me in the right direction, it would be appreciated!!

Have you tried swapping cyl 8 coil with say cyl 4? Clear DTC’s after the swap and see if you now get a P0304. If so, then it’s a failing coil.

If you already tried that, then start looking at either the connector or harness to coil 8 and see if there’s any damages to it. Do a continuity test on the connector.

 

[19gtMD]

When you changed the plug how did it look? Was it wet, cooked, or anything else? When i was having plug issues i swapped coils, and changed plugs at first. My issue was solved and it stemmed from the intake manifold, and oil fouling my plugs. The solve for me was getting an oil catch can on my driver side, because i had one on the passenger side.

 

[Supreme_5.0]

***Update***
So I wound replacing the drivers side O2 sensor and that fixed the cylinder misfire. The O2 sensor looked like it had a lot of buildup on it, so I assume it went bad. Just wanted to give you guys an update!!

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