05 Mustang GT Random Misfire

[RedRoush3v]

I tried the 08-10 coils and that didnt change a thing. Really lost now all i cant think it to be is the ecu but thats not something i really wanted to replace. I sent the ecu to a shop a month or so ago. They tested, said it was faulty and told me they fixed it but that changed nothing as well. If anybody has any ideas lmk.

 

[StockishS197]

I tried the 08-10 coils and that didnt change a thing. Really lost now all i cant think it to be is the ecu but thats not something i really wanted to replace. I sent the ecu to a shop a month or so ago. They tested, said it was faulty and told me they fixed it but that changed nothing as well. If anybody has any ideas lmk.

Just to confirm as I don’t think it was explicitly stated, you are using Ford/Motorcraft OEM coils, correct?

I ask because aftermarket ones can throw all sorts of issues. Personally went though this with some aftermarket “premium coils” chasing a very subtle misfire without any codes. Turns out, it was the aftermarket coils that were less than a year old.

 

[RedRoush3v]

Yes, i bought them straight from ford performance. Didnt want to run into that mistake and get stuck in a loop of troubleshooting more than i already am lol. Plus i heard the oem ones are fine even for performance builds. I also did a kam reset after the install and that didnt change anything.

 

[RedRoush3v]

Update! Took the car to ford for a diag and they told me everything checked out and looked good and they summed it up to be bad fuel. Now i have refueled since the new engine was in but didnt let it go empty before so i suppose its possible that some of that bad fuel was still making its way around. Feel like that may have been the cause of my engine blowing in the first place. Note to self, dont get gas at safeway for a performance build lol. Hopefully that was the issue but i have some doubts. Im just gonna drive the car and see what happens. Ill update this if something comes up.

 

[Pentalab]

What octane gas are you buying ?

 

[RedRoush3v]

91 always, nothing hogher is available near me