hmmmm interesting thread.
i just did an engine on a 97 F150 with the old 4.2. the truck was a $500 junkyard find by our client as it had a siezed engine. we did everything ... rebuilt block and heads, reman injectors, reman starter, reman alterternator, water pump etc etc etc. the only used parts on the truck, generally, were the front end, rear end and the tranny. everything else was done.
after we did the swap we had a hard time starting it. every start would flood the engine. the only thing i could do to get it running was to pull the plugs and dry them off. with that i did the cold start sensor and things sorted themselves out - for a while.
the truck is still at my shop as the cold start issue (and winter, lol) wont go away. leave the truck inside overnight at it starts like a champ. leave it outside in the cold for a few hours and it still wants to flood itself upon startup. and when it does start when cold, the idle is rough. no check engine light and no misfire.
i'm leaning toward the regulator on the fuel rail on this F150, and that might be something to check out on your truck too.
With that F150, if an injector were leaking down then:
- only one plug should be wet when pulling plugs
- it should flood the engine when it's warm, too
For both your truck and the F150 it sounds like it might be that regulator. The cold will do funny things sometimes.