Didn't you have quite a bit of rust in the fuel filter when you changed it? To make it dependable, dropping the tank, either repairing the float level for the gas gage, or replacing the fuel pump assembly. You need to clean the rust out of the tank. Dropping the tank is really not that hard. You can use a floor jack with a 2 x 12 4 foot long to support the tank while lowering it. Of course, the less fuel you have in it the easer it will be to work with. If it wasn't for the rust and the float not working, I would suggest installing an external fuel pump.
Good luck.
