Hey, I have an issue with missing firing that happened out of the blue and isn't consistent. When I relocated my wiring harness that was under my front driver side wheel well I unplugged the battery ever since then I have had a miss firing issue. It sounds like a dead miss fire. When I un hook the battery for a couple hours and hook it back up it runs perfectly for 5 minutes then starts miss firing again. Every time I unplug the battery terminals for a lil while and connect them again it runs fine and then starts miss firing about 5 minutes later. Anyone had this issue before??? I went back and made sure all the connecters from the wiring harness were connected properly and still have this issue. Please post any information that could potentially help me I am completely lost at this point and don't know what to do next. Thanks,

 

year and mileage? when was the last time the o2 sensors were changed?

 

92 SC300, 192k miles on the body but the motor was completely rebuilt 30k miles ago. The 02 sensors was hard wired in about 3 months ago when I installed my emanage ultimate piggyback system.