So first,, yea, I'd think coincidence....

But next, in my experience, a bad IDM (yes, "runs" the injectors) is less likely to have just a single injector issue as the cause (usually a bad IDM kills the whole bank). In a 2000, the most likely place I'd check first for that would be in the wiring.

Either chafing that occurs on the bottom of the wire bundle going to the injectors as it leaves that big square plug (42-pin) above the dr side valve cover and often rubs on the valve cover itself as it goes towards those UVCH connectors.

OR, in the UVCH plug ->

 

First, thanks for your help.

I'll get the passenger side valve cover removed and have a look.

I really find it odd that it didn't have this problem before.

 

Next time it's running bad disconnect the ICP "injection control pressure" sensor on the top of the drivers side head and see if it runs better. It can come go and defaulsi to 500 psi when disconnected. You can also look at the end of the plug and see if you see any oil, then it's time to replace even if it's still working ok (when disconnected at idle it still runs bad)

 

Next time it's running back disconnect the ICP "injection control pressure" sensor on the top of the drivers side head and see if it runs better. It can come go and defaulsi to 500 psi when disconnected. You can also look at the end of the plug and see if you see any oil, then it's time to replace even if it's still working ok (when disconnected at idle it still runs bad)

Coupla things...


First, the default pressure that the PCM sets to run with once unplugged is actually around 2,000psi (500 is the PCMs minimum for starting but it couldn't run well if computed to be that low, the IPR% would be too high for driving).

Next, this whole "Oil in the ICP plug" is much overblown and NOT, in itself, a reason to replace this expensive sensor (but yea, if unplugged AND that cures an issue you're having, replacement is needed). Inside the ICP sensor is an O-ring that holds back some pretty high pressure and, as that ring ages, it can bypass a bit of oil and the sensor can still work just as it should. At this point, my guess would be that most of us with original ICP's would have oil in there and not have any issues from it (remember, Oil is NOT the problem, it has No Effect on the electrical connection but rather just an indication of a tired O-ring).

And finally, the OP has been told (not sure this is a proper diagnoses) that he needs a single injector and a bad ICP wouldn't really be the cause of that (all-too-often, shops who don't know the 7.3's injection system, will call #8 injector bad because of a misinterpreted CC test).

 

Just replaced the IDM on my 2000 7.3 and when picking it up the
shop said it has a bad #1 injector. That it was throwing a code.
I got in the truck and it starts and ran fine.... until about about 5 miles down the road
when the CEL came on and it started running like crap.
I pulled over, shut it down, waited a minute, then restarted. No code. Ran fine.
Another 5 miles or so and it does it again.
Before changing the IDM, I had zero problems with injectors.
I'm thinking the rebuilt IDM is the problem since it runs the injectors (I think).
The shop said no, that it was a bad injector.
Opinions, please?

On a side note: speedometer isn't working now. Coincidence?

What ended up being the issue? as I have the same symptoms