F150online Forums - 1988 F350 Fuel Level Fail

5.8L, single centre tank, in-tank pump/level and in-line pumpLevel stays at Full, until some level around 1/2 tank, then level starts jumping/erratic.Four-pole connector on pump (Orange/Red-B/Yellow/Black wires):
- Red/Black stripe has power all the time, 11-12v

- Yellow has power when key is on, >7 v
- Outer Orange and Black lines appear grounded fine, as conductivity shows fine across them

Appreciate any insight.
Side note, where is fuel filter located on this truck? I found the canister but nothing else in line?