Hello all. I have a 2002 Excursion 7.3, 218XXX miles. Its been mine for the last 5k miles. It is all stock and has mostly highway miles up to this point. My issue began a week ago. Monday, driving on a cool day(39 degrees), after a slight downhill while waiting at a light, it begins running as if its out of fuel, like a miss, rough idle, almost no power. It has a full tank of fuel. Limp it home. Shut it down, fires right up no issues. No codes, no smoke.
Tuesday, take it out again, about a mile from home, issue repeats. Only this time, the condition stays through a restart for a couple of tries. Finally get it to run normally and quickly get it home.
This time I get a code. I'm using FORscan.
Friday I got time to play with the truck a bit. Scanned it, get P1316. Based on the advise here, I decided to check the UVCHs. Removed both valve covers, ohmed everything out, everything to spec. Understanding that the ohm test isn't necessarily the final word, I do a buzz test and a cylinder contribution test. Everything sounded great, called it a day.
Today, tried to start, at this point it cranks well but won't start.
Rescanned the engine. P1316 went away, and I got a new code. I forgot to write it down, but the description was bad circuit to the IPR. Thinking I have not have snugged up the main harness well, I disconnected it, taped up any/all wires that looked like they had any rubbing damage and reconnected it. The code was still there, so I took a look at the IRP. I checked the end nut to make sure it didn't work itself loose, made sure the plug was still connected. Went back to the truck, cleared the codes and tried to fire it again.
Still won't start, has a stumbling turnover. The IPR code has gone and is now replaced with P0683. Checked those connections as well, still won't start.
To my question, what is my next step? The codes are wandering around the engine bay, do I begin to suspect the PCM? I do plan to drop the tank and check the in-tank filters. I did confirm the fuel pump is working. Fuel bowl is full. I have not run a fuel pressure test yet. Any advise is appreciated. Thank you.