New to Powerstrokes. Need help with DTC's

[Bullitt#829]

This is my first powerstroke and I have a few DTC's that I need help with. I currently have 7 codes. It is a early 99 f-350, 6-speed, and 4x4. It is completely stock. I have posted these questions on 2 other websites with out a single response. Hopefully you guys can help me out.

P0460-Fuel level sensor circuit A malfunction
I am sure my sending unit is bad because my gauge always reads full and that is probably throwing the code.
P0470-Exhaust Back Pressure Sensor Circuit Error
P0475-Exhaust Pressure Control Valve Error
P0478-Exhaust Pressure Control Valve High Input
I have cleaned the tube between the manifold and sensor with no luck.
P1393-Glow Plug Circuit Low Input Bank No. 2
P1395-Glow Plug Monitor Fault Bank No. 1
I have high resistance on one glow on each bank and the wiring harnesses aren't looking the greatest so I ordered OEM glow plugs and will be picking up new harnesses for both sides. Which should fix the 2 glow plug codes.
P1670-EF feedback signal not detected.
This is the code that stumps me the most. Everyone that has had this code either had a truck that wouldn't start or barely ran. My truck runs just fine. It does have a little bit of trouble starting after sitting for a while.

[Costnar]

looks like I am getting a p0460 code for a bad fuel level sensor. Still have the digital miles left in tank gauge on dash which seems to be working. Is that a redundant system? Guessing the tank has to be dropped to replace the sensor? Truck is an 2006 F-250 powerstroke diesel harley edition. Thanks for your help.

["Stroker 8"]

[mazsecond]

Wish I could help you out but I'm a 6.0 guy. Heres a free
Someone will come along and give you some advice.
Goodluck