94 f-250 fuel problems

i have a 94 ford F-250 and it is lacking in power. the truck has been parked for about 8 mths. after checking to see if the gas was still good and installing a new battery the truck stats and idels high. i adjusted the idel and some other minor shots of wd40. the truck would not pull out in drive so i changed the in line fuel filter (the cartridge one on the frame) the symptoms lessened but not quiet 100%gone. there are two tanks and i cant find the other cartridge filter. Is there another filter and where is it hidden???

gasoline or diesel ???

gasoline

There’s only the one 3" in-line fuel filter on the truck. Each in-tank pump has a little sock filter on the bottom sold with the fuel pumps.