Stumped

[Field Worker]

I have a 2000 250 SD 7.3 with 280,000 on it, It been strong running truck but has an issue I can't seem to find.

Every once in awhile, (sometimes 4 times in a row) the engine while driving, acts like its running on 4 cylinders but does not shut off, but looses all engine power. I put it in neutral, shut off completely, then re-start it, sometimes this clears it up and runs fine the rest of the day.

What I have done so far:
changed the under valve cover harness, glow plugs, glow plug relay, exhaust back pressure sensor tube (this was broke in 2) cleaned the back pressure sensor, removed the IPR and disassembled and cleaned + add new orings, replaced the ICP sensor (it was leaking oil).

I run the AE, all the cylinders during the buzz test test ok, comp tests ok.
Only P1316 shows up as the codes.

Could this be a ICM going bad? I hope that anyone who experienced this before can help, it is dangerous when pulling a trailer or in heavy traffic / Mountain passes.

[Field Worker]

I see I'm not the only one stumped

Happened again this am but not again since I restarted

[1997f-350]

i'll bump this for you, and maybe give another chance of someone else giving you help. i had something like this on my old 97, and it was right around that mileage too right before i got rid of it. think it may have been a cam sensor, but i'd like to hear more opinions on it.

[inkrtr26]

When mine did that it was IDM. If you can get one to try, I would suggest it.

[Field Worker]

I have replaced the Cam sensor with the new grey one, then changed it back to the original black sensor and kept the grey as a spare.

I thought the IDM maybe the problem, it just does not make sense to have the CEL come on and run on a few cylinders once during the day, if the real problem was a wiring issue, that would cause it to be continual

I know the IDM is located under the left front panel, and I had it out two years ago, but do not remember if I had to remove the plastic panel behind the emergency brake to remove the bolts. Anyone have the proper way to remove this?

I also see that the glow plug relay does not always kick on when I turn the key on, I believe this is actauted through another smaller relay first (I changed these out also) I have to keep turning the key on and off a few times until I hear the amp draw from the GLR, otherwise I will have a no start problem, usually this is when it has sat overnight in the garage ( general temp inside 20 deg)

[Field Worker]

Well, I believe I found my issue. It has run for two weeks now without a problem.

A couple of months before I changed the wiring harness on the passangers side but only removed the drivers side to access the glow plugs, (which I changed on both sides) since this was recently changed out by Ford (stick it to you service bay) After removing the valve cover I noticed the harness coupler had a gap only about 1/8" at the front side, but if you visualize the contacts and how they connect, this drop takes away quite a bit of the available surface contact area, thus causing my engine to act like its running on a few cylinders. I could not implement this US Quater fix because the plastic clip was broke, So I drilled a 3/16" hole in the harness at the outer edges making sure I do not drill through and nick the terminals inside, and cross connected these together using plastic wire ties (2). Like I said, it has run great eversince. Ford really should look at a better way of connecting these, but until then I recommend this. I drilled the 3/16 hole only because the wire tie I had needed that size of hole, If I needed to due the other side I would look at something smaller so the tie is a bit more flexable and less chance of knocking the terminals inside.