Okay, having major issues with the early 99 F250 7.3. Code is P1670, which apparently could be anything in the injector system - thanks a lot. BTW, the factory service manual, two volumes, seems to be the worst factory manual I've ever seen - I usually buy one for every vehicle. Impossible to find anything in. But I digress.

- Tried to start last week, it ran really rough and wouldn't stay running without a foot on the pedal. Acted like the exhaust back pressure valve was engaged, but temps are 70+ so it shouldn't be doing anything. I drove it up and down the block a few times to try and get it warmed up/unstuck, but no change.
- Hooked up my old code reader, showed P1670.
- First guess is Injector Module (IDM), ordered a reman from Rockauto.
- Disconnected the injectors, harness looks fine, connectors fine.
- Ordered a set of boots, fuel filter, and wastegate vacuum lines from RiffRaff - after 22 years the old beast's parts are deteriorating.
- Replaced the IDM - cleaned the connectors with air, looked fine. Rebuilt unit has '2001' etched on the side.
- Tried to start - same thing, maybe even worse.
- Remembered I had a couple spare CPSs, Ford, light gray, still in plastic. Replaced CPS.
- the CPS bolt just doesn't seem to tighten. It never gets more than a little past finger-tight. CPS is pressed all the way in, and the metal bracket isn't loose, but the bolt is just barely snug. Is this normal?
- Tried to start - same thing, but now even extra pedal won't keep it running.
- My next guess is the injector harness under the valve covers - ugh. I've never opened them. But I got new plenum boots and plenum inserts, so if I'm doing those, the valve covers shouldn't be that much more work, right? Right? Please tell me that's right.

So, questions:
- Is the CPS bolt supposed to stay just 'snug'?
- What's the likelihood of the injector harness coming loose under the valve cover(s)? I know the quarter mod is common, but it seems like a lot of work to get at.
- How hard is it to remove that stupid EGBV? It rarely gets 'really' cold here, and when it does I'm not usually driving anyway. The whole contraption seems like a bad idea.

I tried to search before posting, but the Tech folder seems busted.
Thanks everyone!