Michael Gain
Full Access Member
You said three of the four spark plugs had the oil/fuel on them. Was number 7 the one without residue? If so, it sounds like fuel, only in so much as that cylinder would be the most lean on the bank.
To your other question, the other injectors could create a cascade effect towards a misfire in #5. They all "report" to the same O2 sensors on that bank.
I would be interested in your fuel trims. I bet they are lean on that bank. The injectors dump more fuel to compensate. Number 5 injector is new so it sprays more fuel by injector pulse-- causing the plug to become fuel fouled.
That said, it can be something else causing a lean condition; other than the injectors... Vacuum leak, MAF sensor, O2 sensor, etc
To your other question, the other injectors could create a cascade effect towards a misfire in #5. They all "report" to the same O2 sensors on that bank.
I would be interested in your fuel trims. I bet they are lean on that bank. The injectors dump more fuel to compensate. Number 5 injector is new so it sprays more fuel by injector pulse-- causing the plug to become fuel fouled.
That said, it can be something else causing a lean condition; other than the injectors... Vacuum leak, MAF sensor, O2 sensor, etc