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Im at the end of my knowledge and diagnostics with my truck. 2022 F600 7.3 rollback. 109k on the clock, 60k on replacement motor from ford. Recently under load, the truck started with cel flashing, loss of power and code P0171, and cylinder 1 & 7 misfire. I replaced pcv and hose, all new coils, new updated wires, and new plugs.
Now, when I accelerate and get over 3k rpm, cel flashes. Loss of power, and still cylinder 1 & 7 misfire and random misfire. When I ease off throttle, light goes out and truck runs smooth. Did a compression test, all.good. using a top of the line snap on scanner, I checked injectors, fuel pressure, and other possible fuel issues.
What am I missing before I take it to the dealership?
I would suggest to swap plug wires with cylinders giving you problems with cylinders with no problems. If the CEL follows the wires, replace all of them with the RV style or updated Plug Wires. I bought a 2021 Motorhome that was spitting and coughing and kicking out CELS. New Plug Wires fixed it. No problems since........
Well...... wiring integrity to the coil from pcm (3 to each coil I think)? Look at where they all plug into the pcm for any obvious problem like rodents at work.
The ignition coil connector on the 7.3L has three wires: check these. Not sure how.
Trigger/Control Wire: Signal from PCM (low voltage pulse).
Ground Wire: Engine/Sensor ground.
Power Wire: \(12V+\) from the power distribution box.
Two fuel injectors bad , possible but not likely.
Bad PCM, again unlikely.
What ever it is DO follow up and tell us what it was after fixed.