You say the filter flows fine so can you place a bucket under the filter with the tank side attached and the engine side in the bucket then turn the ignition to ON. This should run the fuel pump for two seconds. If you have flow then it's not the pump that's the problem. When I had my fuel pump fail the gauge was unaffected. Is the fuel pump relay working? You say the fuse is good but do you have 12V getting to the fuse? I looked at the schematic and the pump and gauge do not share a common circuit.