99 F250 Feels like a miss when accelerating and when level speed out.

[priorityrepo]

Trying to help a friend out so any help is appreciated.
99 F250 7.3 4X4 W/Banks Six Gun and Trans Commander 244k
It feels like a gas engine with a miss when you first accelerate and when you run at consistent speed or RPM.
When it started he took it to a Ford dealer and they pulled the following codes:
PO476 Exhaust pressure control valve performance
PO541 Intake Air heater circuit low
P1140 Water in fuel
P1211 ICP pressure above/below
They replaced F4TZ 6731 A : KIT - ELEMENT & GASKET
16 Each DOIL - Not sure what this is but this is what receipt says.
Changed oil and filter - Drained water and fuel seperator
Retested ICP is stable. #8 injector fault.
Dealer wanted $1100.00 to repair injector so he decided to take it to a well known diesel shop and this is what they did per there receipt.
7.3 ab fuel injector $268.45 (part)
Troubleshoot for #8 injector contribution fault. Install bypass plug in tuner. Run contribution and buzz test. R&R intake pipes and valve cover remove #8 glow plug and run compression test (cylinder had 500 psi at time of test) replace #8 injector. Did not fix problem. Run continuity test from IDM to #8 injector (passed). Replaced IDM and Ecm with test units. Still has problem.
Suspect engine has internal cam or lifter problem on #8 cylinder.
Customer declined repair. (all info of receipt provided by shop).
Doesn't end there. Someone put him in touch with the supposedly 7.3 guru that works for a large ford dealer that works on the side for a few people and this what he did.
Said he found a short in the wiring. Pulled the fuel tank and changed the screen on the fuel pump. Changed the fuel filter. And changed the fuel regulator back by the tank. This is what he told my buddy and that he was stumped and doesn't have any more idea's. So my buddy is about $1200.00 in and still has the original problem. The check engine light is not on but I have not had a chance to scan it to see if there are any codes stored. I do apologize about the length of my post but I just wanted to be as detailed as possible.

[GoFastPadre]

Maybe it is a lifter or valve problem. I'm with the so called guru,

[DieselSVT]

Does it have the Grey CPS? I chased a #8 injector failure for a bit. I think I changed it for no reason.

Does it miss at idle? Or certain RPM range?

[priorityrepo]

I'm not sure about the CPS but i will look when he comes later today. The miss seems worse around 1500 RPM'S but it does it when you are accelerating from a stop or low speed and when ever you level off at any speed or RPM. But it does seem more consistent around 1500 RPM'S.

[DieselSVT]

Not for nothing I went thru a miss at 1500 that I swapped a bunch of parts trying to figure out. IDM's, Injector harnesses, #8 Injector, IPR, ICP. It turned out to be injector O-rings. They were toasted.

Mine ran great cold. It would accelerate up to 1500 and kind of get stuck there skipping and just kind of breaking up so to say. A little more gas and it smoothed out. Mostly in 2nd and 3rd gear (auto). It would only do it after about 15 minutes of driving or when warmed up somewhat and after sitting overnight it would white/blue smoke a tad on startup. It would also sound "ragged" or break up at a certain foot pedal position. It would decelerate funny too almost like there was an injector hanging up.

If you ease your foot into the pedal more or less does it go away?

Just sharing my experience. Maybe you can benefit from it maybe not. Keep us posted.