Thinking about the dust in the filter, that may be normal for unleaded fuel. The old days leaded fuel left a varnish when it dried but todays fuel is dusty. The unleaded race fuel I run has a fair amount of heavy particulate that needs to be strained before going in the car.

Cheers, Charlie
If It ain't broke, Modify it!
87 Montero turbo Converted back in Spring1989
95 Montero SR 3.8 DOHC Only one?
93 Pajero 3 door 6G75 Mivec with paddle shifted 5 speed
Then a Gen2 SR with full coil independent suspension.