My 86 f-150 300I6 acts like it is running out of gas to where it will sputter and it will die for a few seconds and then it will fire back up again and it will keep on doing this till u stop. It will only do it after you drive down the road for about 10 miles. I know its not out of gas because i had just filled up. and once the truck cools down it will run fine. i was thinking it was the fuel pump and/or the fuel filter. any help would be great

 

It sounds like your truck is vapor locking.

Make sure the heat riser valve is working properly on the exaust manifold and is not stuck closed.

Also make sure the heat blend door in the air cleaner is not stuck closed, or open to hot air.

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Also have the ignition module tested. A bad ignition module can cause simular symtoms when they get hot.

Hope this helps

 

I know this sounds silly....but it is the world of mechanics. My 84 did this too and after I spent alot of money and never fixing the problem I noticed a small hole in the gas tank about 3/4 way up near the top. The hole was smaller than the eraser end of a pencil allowing the fuel pump to loose its prime. Imagine that, I never noticed the problem early becasue as I was repairing the truck to make a daily driver I never filled the tank, only enough to start and rund the engine. I know you said you filled up but check the top of your tank and your lines also. Also like previous: check for vapor lock. Good luck.

 

just had the exact same problem on my 84 f 250 replace the ignition module mine would run perfectly and about 3 or 4 miles down the road would die like it was out of gas , if you tried to restart it would pop through the carb but would not restart. if i let it sit it would start after about an hour it got worse untill it did not start at all

 

If you have fuel injection, you might find that fuel pump pressure is low, indicating that you might have either a bad in-line filter, or, a bad fuel pump. Been there, done that.

 

If you have any rubber fuel lines check them they may be cracked and sucking air

 

i have talked to a few friends about this problem and they believe that it is the coil. one friend had the same truck as mine and he had the problem and that fixed it

I dont think that i would have a hole in the fuel lines because i park it on a clean cement floor all the time and there has never been a gas leak.

 

that's not it. It may be flooding (too much gas) or too little gas. You will not necessarily have gas on the floor with a hole in the line. You need to check all the things other people mentioned.

A tune up will go a long way - it's probbably past time for a new cap, wires, and plugs. A carburetor adjustment would be good, and setting the timing. From there, you can start trying to find the problem.

 

I replaced the fuel filter and one section of the fuel line where it was wearing away from the inside out.It doesnt do it very often but it will do it.

It has only died completly once all the other times it just dies for about a second then it is fine again, for about 15 seconds or so then it will die again. It usually only does it when I am tring to keep a constant speed and it started doing it around 45mph but if i would down shift from 4 into 3 and hammer it, it would run fine. But now it does it when im running 60mph. anymore help would be great.

 

Mine did almost that same thing its carburated. Check and make sure the distributer is on their tight.

 

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before you waste $$$, spend about $20 and replace it with a new one. Good Luck

 

Let us all know what is going on, I replaced all of my fuel delivery and ignition before i relized it was a lose distributor when I went to replace it. I felt a little dumb after that but i am not a pro.

 

the reason why i havent replaced the ignition module, or the coil, or the distributor is because i have been told that it would just completly shut down. which has only happened once and then i thought that it was just out of gas and i didnt want to drain all the gas out of the carb so i just shut it down. after i replaced the fuel line and the filter it has only done it twice within about 2 weeks and that has just been starting out from a stop sign and tring to get up to speed. I can tell when it is going to happen because my truck starts to lose alot of power and it starts to shake (more than it normaly does LOL). im taking it in to a mechanic to have him take a look at it and to check all the inginton module, coil and distributor. but sence the fuel line and filter have been replaced it been running almost fine.

 

You can take the ignition module to a parts store and have it tested. The ignition module can go bad, and the truck will still run.

The most comon problem for Ford ignition modules is that they have a intermitant fault when they get hot. In other words they run and work fine until the module heats up, then intermitent faults develop.

Don't let the old misnomer fool you. Your truck can run on a defective ignition module, but it wont run for much longer, and it will keep getting worse until it quits for good.

Holes in fuel hoses, can cause a "vapor lock like" condition, sucking air etc. A plugged fuel filter will block fuel, and act like it's running out.

Have you check all the things that we asked you to check before, Manifold heat riser, intake heat riser doors, etc..?

It only takes a few minutes, and if they are indeed not working, right, a can of WD-40 or other such penetrating oil most likely will get them working again.

Oh, by the way, do you have the anti stall dashpot attached, plugged in if applicable, and working? keeps vehicle from stalling on hot days.

Hope this helps.