When your car is idling/part throttle it’s using the O2s to figure out how much fuel to add/subtract to hit a stoich (14.7) AFR. The ECU will use that adjustment (fuel trims) to add fuel to your PE map under WOT if they’re reading lean, but they won’t take away fuel from PE if you’re running rich.
So in 5th/6th gear at part throttle <2000rpms your fueling is coming from what your O2s say is stoich. If your car is running lean your fuel trims will add fuel till you’re running stoich. If your car is running lean beyond the adjustment of your fuel trims the computer will throw a lean code. So unless it’s just one injector that’s screwed up and one cylinder running lean I doubt you’re running lean and it’s causing the misfire.
If your spark plug is looking clean maybe your injector isn’t firing? Since you already tried swapping injectors maybe it’s the injector harness wiring?
ALL of my spark plugs looked clean besides #7 which is odd because thats not the cylinder that is registering as a misfire, although it is right next to #5…#7 plug was dark brown on the whole entire plug while the other 7 looked still like new.
That is wierd because if one injector isn’t firing then the other cylinders in that back usually run rich since they share an O2 and the computer tries to compensate.
good point. very well could be, but if thats the case, the problem still lies with electronics, because hes getting alot of unburnt fuel in that cylinder if its even got the chance of cylinder wash
dead slugs suck… sorry homie. northstar or allstar are ur logical choices… OEM block should be just fine. no need to go building something out of pocket YET if theres a chance of them warranty-ing it.