N14 fuel restriction question

[race7820000]

I have a 98 n14 in a freightliner, the fuel restriction gauge will go high at idle but when you give it throttle it will go down and stay down. The higher the rpm the lower it goes.

It does the exact opposite like if you have a plugged fuel filter.

Is there a return check valve or a screen or something?

It's a mechanical gauge

I changed fuel filter and took out and cleaned the check valve by the fuel inlet that runs from line by the computer to filter.

Thanks