I just bought a 90 mighty max with a 2.4 in it a month ago. it has 260000 miles i drive it to work and back home to save on fuel. well last week it started to act up as if it wasn't getting power and would run rough for a few miles than act normal but now it just runs rough all the time. i changed plugs wires fuel filter. still same problem. today i found a gas leak coming from the top of the gas tank off one of the steel lines from the fuel sending unit. I can't find the right fuel sending unit anywhere. what should i do? also could this be why its running rough? I really like this truck so any help would be greatly appreciated.