1999 Mustang with Kenne Bell Supercharger: P0305 and P0355 Misfire, Coil Failure Diagnosis
I own a 1999 Ford Mustang equipped with a Kenne Bell supercharger. Recently, I've been experiencing misfires in cylinder #5, detected by Diagnostic Trouble Codes (DTCs) P0305 and P0355. The spark plugs are relatively new, which led me to suspect a faulty ignition coil. To test this, I swapped the ignition coil between cylinders #1 and #5. After the swap, the DTC shifted to cylinder #1, confirming that the original coil in cylinder #5 was defective. I replaced the coil with a new one and cleared the codes. The car ran smoothly during initial startup but began misfiring again within less than two minutes of driving. Upon returning home, I noticed a distinct electrical burn smell when opening the hood. Rechecking the DTCs revealed P0355 once more. After removing the coil from cylinder #1, I found a visible crack at the base of the coil housing—indicating an internal short and burn-through. The original faulty coil in cylinder #5 also showed the same damage. This suggests that there is an underlying issue causing ignition coils to fail under these conditions. Given that the Kenne Bell supercharger has been installed for three years without issues, I'm wondering if the high-performance setup or increased electrical load is contributing to this failure pattern. Before replacing additional coils, I'd like to understand what might be causing such coil failures in a 1999 Mustang with a supercharged engine. Any insights or recommendations would be greatly appreciated.