Morning fellas have somewhat of a head scratcher.

truck in question is a 96 f150 5.0 4r70w 2wd. 313k miles. Owned for almost 4 years now mostly trouble free.

about 8 months ago I had a fuel pump fail finally on it and I replaced it with a new precision pump with a life time warranty. All was right in the world for about 2 months then it sat for a week without being cranked. The tank was low but not empty. Around a 1/4 or so. I started it up one day and it went as well as it has for nearly 4 years. I drove it around the block and it did fine until I turned and went up a slight hill headed back home and it started acting like the transmission was stopping to pull. Increased throttle and made it. By the time I got home it was awful. I could floor it and it'd babble like it had a 2 step rev limiter set at 3000 or something.
I removed the bed AGAIN and pulled the pump assembly to inspect trash in the tank. It was CLEAN. My first thought was a dead Chinese pump. I got a warranty pump and dropped in and no improvement. Ever since then it stumbles on first crank sometimes. Doesn't stall just runs like it's running out of gas. Tap the throttle and it acts right.

I ended buying a 94 f150 for a daily while the 96 was acting weird. Well it ended up sitting for a while until the 94s pip died. I messed with the 96 one night and recalled steve83 always telling people check body grounds. The one on the fender by the battery was loose and kinda cruddy so took a brass wheel in a drill and cleaned each ground and the fender til they looked chrome. Viola!!! Problem solved. It hadn't ran that beautiful since I've owned it. I cleaned the computer, firewall to intake, and the 2 on the radiator support. It ran better still. Even found the top end speed limit i didnt know it had one night, allegedly 😉. But The stumble/low idle would still happen but much less frequently. It normally goes away on its own after a a few seconds. If it persists a quick tap on the throttle solves it and it idles fine.

I've checked fuel pressure it's fine. Checked for vacuum leaks too many times to count. New bwd tps. Coil. Has older but still good msd cap with brass terminals. Plugs are only 30k old or so wires too. New fuel filter. I've cleaned the iac. some but not enough improvement to see if it's an iac issue. I replaced it with one off the 94 and it virtually stopped doing it then started again randomly.
upon running codes it normally says egr insufficient flow. Which is normal because my egr valve has been blocked off due to the tube getting broken one day, for 3 years prior to the original fuel issue. If it were a problem I'm sure it wouldve surfaced in 3 years lol.
the cold start stumble has gotten a little more frequent lately but again doesn't ever affect drivability. But now I'm showing a egr excessive flow now?!?!
this particular truck DOES NOT have the egr position sensor on top of the valve. It has a dpfe sensor on the front of the upper plenum which is still hooked up. The green vacuum feed to the egr valve is plugged and evr is still hooked up and plugged in. No other codes besides the excessive flow.
now that I've gave a detailed history of the problems as of late I have some questions. I'm not ignorant about efi I understand it pretty well but I'm always learning.
I'm curious if the egr vac solenoid is failing causing it to stumble. iirc the timing is doped a little for the egr and cold starts.
could I just be over thinking it and the iac is just the problem all along? Could carb cleaner infact kill them?
Any thing I'm over looking here???

it's not that bad to Deal with but I'm somewhat of a perfectionist and if a vehicle has the ability run right it should.