Dreaded p0308 Cylinder 8 Misfire

[Gturo_5.0]

Alright so, I have a 2011 Mustang GT 6M that I purchased used at 84xxx miles. At about 89xxx miles the CEL showed up and the only code is p0308. I knew this was a common issue on these cars but I checked the main things that it could be like changing spark plugs and such. I swapped the coil pack with cylinder 5 and later on it came back as p0308 again. Now i'm worried. The code seems to come and go. sometimes for days at a time it will be gone and wont even show up as a stored code. I have checked on cold starts and warm starts to see I can spot any blue smoke from the exhaust and keep checking up on my oil and its not burning it at all. So I really just want to know if this seems to be a cylinder issue because i definitely can't afford to rebuild or replace my engine :/ P.S- The only mods it has are an Airaid cold air intake, Airaid Throttle body spacer, and a BAMA 91 race tune. All of which were installed by the previous owner.

 

[96gt02]

I believe the second to last line sums it all up, BAMA 91 race tune RIP motor

 

[sur_real1]

Do you have anyone in your area with a Ford VCM with IDS? I'd hook that up and do a full network check to see if any sensors are failing or starting to fail. Of note, your handheld tuner cannot perform these deeper checks. Could be a short, failing sensor (maybe crankshaft positioning sensor), or all the way to something mechanical. But if the engine isn't making any new noises like sand in the crank case noise or obvious rod knock, it's probably electrical. With that being said, the very first thing I'd do is get a VCM hooked up and have it test all modules and connections for failures. Then get a borescope and check the cylinders. If all is well there, get a datalog and send it off to your tuner.

 

[Gturo_5.0]

I believe the second to last line sums it all up, BAMA 91 race tune RIP motor

Yeah i heard that the bama tunes aren’t too good but the guy i bought the car from didn’t give me the tuner he told me later on that it had a bama tune on it so i couldnt even unmarry it to change it.

 

[basspro302]

If it’s something mechanical you should feel the misfire. Change the plugs swap coils. The ford 3valves would have misfires like that on the highway under certain loads and it was just the coils breaking down. Try a crank relarn with a scan tool or sct tuner.

 

[Gturo_5.0]

Well i feel a slight “misfire” feeling at idle but its no worse than my buddys who has a 2017 GT and his is brand new i just assumed thats how these engines ran.