86 F250 keeps dying

[86F250_7.5_4x4]

Okay so I bought this f250 about 2 months ago and was driving it around town never made any huge trips with it, but last week I was going on a 2 hour trip and 20-30 minutes in the truck just randomly dies on the highway, I had to pull to the left side and tried to crank it over, but wouldn't go. I had to wait about 10 minutes then tried it again and it started, but it was running rough. I pulled into a Walgreens and waited about 20 minutes until my dad came up there and we figured it was the fuel filter because the hose was too big for the fittings so we thought it was sucking air. Put the new filter on, started right up and drove it to a gas station not far away. While I was at the station it died again when I just left it sitting. I waited a little bit more and then started it back up (This time it took longer) I waited about 20 minutes in the shade then just said screw it I'm going to see how it does now. I went on the highway and it must of been about 20 minutes again and it dies. So we get it back to my house after that and start trouble shooting. My dad got a fuel pressure guage and apparently it was only shooting out 4 PSI so we went ahead and replaced the fuel pump, but it still keeps dying. I have put a lot of money into this truck so far and want to keep it running, but I can't think of what it would be. Please help. Info on my truck: 1986 F250 7.5 460 4x4, carbureted, automatic.

 

[SuperCab]

My first thought would be the duraspark box... Don't remember exactly how they're set up on an '86 but it will definitely give you trouble like that if it's going out

 

[Beach66Bum]

My first thought would be the duraspark box... Don't remember exactly how they're set up on an '86 but it will definitely give you trouble like that if it's going out

X2 to what Frank said. My Duraspark box went bad and finally quit and I had those symptoms. Once it starts to get hot it dies, let it cool down and will run again for a bit.

 

[86F250_7.5_4x4]

So far my truck has been running good. I think all it was after all was my fuel pump because this morning I checked under the hood and apparently the guy who owned the truck before me put air hose instead of fuel hose going from the fuel filter to the carb.. Short story short, it had a big hole in it at one of the clamps. I put some fuel hose on it and its running good so far. If it dies again I will start taking suggestions, but my Ignition module is the one mounted on the fender and seems to be fine, so don't think that will give me a problem anytime soon. Anyway, thanks for all of the help guys.

 

[crazycanuck]

The only way your fuel line would "suck air" is somewhere between the tank and fuel pump. From the pump to the carb is pressure, so it would leak fuel from there. 4 psi is fine. I am leaning towards the dura spark box as well. Once it warms up it does all kinds of things if it is on its way out. time it dies, check for spark, another problem area could be ground, the duraspark box is grounded through the distributor. Sometimes that can give issues as well, a bit of corrosion between dist base and block.