Ok so as many of you know I installed a new pump a bit ago. Here's the details.

Fuel tank option NE2 plastic fuel tank.
18 gallon tank.
module code TCH
Pump is Delphi FG0052 More Information for DELPHI FG0052

Pump that was removed was stamped with module code TCH and was OEM from the factory.

Fuel tank was replaced with a tank from a junkyard, Tank was identical in dimension and type to the original.

During new fuel pump install 2x2 connector was replaced with new 1x4 pigtail. No problems with running, starting, or pressure.

Now, The gauge shows full when full and operates normally to half a tank. once at half a tank it falls rapidly untill the fuel light comes on. If I fill it when the light comes on I can only put 13 gallons in which tells me it's giving me a 5 gallon reserve.

My previous pump/module/sender would not do this, when at 1/8 tank I could put 15 gallons in, now it's not like its a BIG problem but it's kind of annoying knowing i can't use about 3 of those 5 gallons of gas because once the light comes on I can't tell how much fuel is actually left.

Has anyone experienced this or have any solution to the problem here?