got a 84 f150 xlt dual tank been havin problems with it. i started it up run about half a mile an cut out and died i switch to a different tank and it started back up with out turnen the key ran fine then i drove about 5 mile and it just died. i sat there for a hour and a half and still wouldn't start. had it towed home were it sat for 2 to 3 hours it started and ran for a bout 35 mins and it died. but when it died it didnt cough or sputter like if you run out of gas it just died as if you turned off the key. so now it will start run for about 45 mins at idel and dies and wont start for some hour cant figure it out changed the coil still does it cant find the fuel filter on it either it should be under the drive door in the frame rail but its not

 

A bit of info about which engine would be handy, as well as knowing if it is carbed or not.
Also, there are 2 different ignition systems that could be in place. Does your's have the module on the dist or fender?

 

sorry about that its a 302, carb, machical fuel pump, magnetic distributor.
module is on the fender big ol grey metal box

we think it might be the condeser off the coil, the coil has a weak spark when we tested it and i also have changed coils so the coils arent bad

 

The fuel filter on your truck will be in one of two places. On the front of the carb (like my '83 302), or inside the carb. The one on the front is like a little canister that screws into the front.
I actually just found out about the kind inside the carb today. There were some that when you took off the fuel line, you pulled it out of the carb and there was this tiny paper filter just past where the fuel line threaded into the carb. Look at the carb and see which one it has.

As for the no-start issue, I had something somewhat simillar with an '84 F150 that I used to have. It had the 351W, but I'd guess the distributors are pretty simillar. It would run and drive fine, until I shut it off. If it was shut off for more than 30 min. it wouldn't start again untill the engine was completely cool. I found out that it was the pick-up coil inside the distributor. I replaced that, and that took care of the no-start problem, but in the process I screwed with the timing and it never ran very good after that. Keep the distributor in the same postition as it was when you took it out and you shoudn't have any problems.