Before my dad died he had bought a 1970 FA100 that had been in an accident. I had known the the truck before the guy had wrecked it so I knew it was in pretty good shape engine used a little oil. Well dad had just replaced the front clip when we found out he had cancer that had started as Colon cancer and spread through out his body. After he died mom caught a sale on re-manufactured engines at a local Ford dealer so she had them put her in a new 390. When it had been wreaked the fuel filler had been bent up so it had been left open to the elements for a while. Man that engine would run then all of the sudden it would just stop. Now this was moms transportation when it did it one to many times she went and bought a used Explorer. Well I needed wheels so I borrowed the truck and it did it to me. I got out and checked no fuel pulled the fuel filter off (lots of fun out on a rural country road in the middle of the night with a almost dead flash light and a leather man tool) sure enough there was junk in the filter I turned up side down and dumped it out and went on my way. Every time it would do this we would do the same thing dump the filter the truck would start and go on down the road. I figured that it had picked up a bunch of sand while the fuel filler was screwed up. Well mom gave it to my eldest niece who's boy friend convinced her to change out the tank. He put one under the bed but in typical kid fashion just did it good enough to drive you never knew how much fuel was in it. His older bother and I had the great idea of standing the old behind the seat tank up in the bed next to the cab. So we went down to the local metal place and had a piece of diamond plate bent up to make a cover Craig built a frame for the bottom of the tank to fit in then cutting spacers the right length and drilling holes in the upper seam of the tank and matching holes in the bed rail we prepared to mount it. When I picked up the tank to hand it up to him we heard some thing in the tank well we turned up side down and shook it and out fell one of those little round seals they put on bottles of gas treatment. It seems that somebody had told mom that she needed to pour the stuff in because the tank only had a rag stuffed in for so long. What we figured out is every once in a while it would get near the pick up get sucked up against it causing the motor to quit running of course in the process of getting out of the truck to clean out the filter we would shake the truck cause it to move off the pick up tube and when you got back in the truck would run.