Hi all,

I've got a 98 formula(91k miles) with a p0307 code. It started off with a misfire under load at higher speeds, then has affected most of the power band except when it's full throttle. There's new spark wires, new spark plugs and new injectors. Compression is good, roughly 150 psi. The most notable thing while trying to trace it was during the injector install. After all 8 were replaced it was running much better than before for a few days, then returned. Other steps to trace it like swapping coil packs were also tested, as well as testing the plug voltages/resistance. It's been stumping me since it's creating a rich condition on that one cylinder, as indicated by the o2 readings. I'm curious if anybody out there has experienced anything similar or has any pointers.

Thanks

 

Buddy's TA had this same code a while back. After trying several things and it always coming back, along with misfires under load. We eventually traced it to corrosion buildup at the connector from the harness to the coil.