Fuel Gauge nightmare

[removalmachine]

Hope someone here has some insight!

93 Sub 5.7 TBI.

Had the fuel pump and sender replaced few months ago. Carter pump, can't remember the name of sending unit.

Immedialty after, gauge would not read properly. Would read from full to about half only. Had the sending unit replaced under warranty - still did same thing.

Third time back they test the replacement sending unit before dropping it in tank. Plugged in, they can move it from one extreme to the other and the gauge reads properly (full to dead empty) - install it - same problem. Order gauge from wrecker - same problem, reads the same as mine.

They can't see anywhere where the float would be hanging up - looks free - and all voltage and resistance at all positions is within spec.

HELP!!!!

Thanks