2015 Mustang GT PP cylinder 8 permanent misfire

Well, seems like issues are just piling on for me. Got a CEL today after filling up gas. Went to Advance Auto to get it scanned and ECU reported that it's a Misfire on cyl 8.

I would tackle this repair myself, but seeing that I still have a powertrain warranty still and that I have popping rear driver side axle and hood corrosion, I will let the dealer deal with this. I just hope it is something simple like the plug or coil, but it may be the intake manifold cracking. I read on different forums that people had cracks develop on the intake manifold which was causing their misfire codes.

Either way, I will keep you all updated!

We have one here right now that is only setting P0308, but it has misfires stored on that whole bank. Tech found the IMRC rod broken on this one.

I had the same misfire in cylinder 8 CEL. The dealership replaced all the spark plugs and the coil but CEL kept coming back on. It wasn't until they replaced the intake manifold that issue went away.

Yeah, well turns out that the powertrain warranty does not cover spark plugs or coils, and if it happens to be one of those then they will charge me $135 just for diagnostics. I will just experiment myself to see if I can isolate it to the coil or plug. If it is not, I will let the dealer verify and then probably change the intake manifold.

For what it's worth, when my intake manifold had cracked, I got p0308 and p0300 codes and the car had a shudder/vibration at very light throttle from 1800-2200rpms. Nothing noticeable at full throttle.