I have a 79 F - 150 with a 351 bored to a 400. I just bought the truck, and it has 5000 miles on rebuilt motor. Recently while going done the highway it started to bog down and sputter. It went from 65 mph to about 35, and chugged and sputtered for about 5 or 6 miles, then took off and ran fine. I drive about 35 miles each way to work, and this happened on the way home. I drove the truck around town that night, and the 35 miles to work the next morning, and it ran fine. The on the way home it did the same thing again. This time it was worse, it acted up for about 12 miles, and then ran fine for about 10. I had to pull off the road to stay out of the way of traffic, and when I did I put the truck in park, and revved the engine it spurted once, and then revved as normal. When I took off the truck ran fine for about 300 yards, and then did the same thing again. I talked to the guy I bought it from, and he said he had just changed the fuel filter, and put a new fuel pump on it. The only way both nights were related is I had just put gas in it before this happened. I just talked to a local mechanic, and he said sounds like a carb problem. I don't attest to be much of a mechanic so I was wondering if you guys had any thoughts or comments. I will probabley let this guy fix it, and he mentioned rebulding the carb. If this turns out to be the best way to go, does any one have any suggestions of things that I could have done to the carb to increase performance while it's off, and being worked on.

 

check the filter but it sounds like your getting water in your gas the ford factory carb filter will not let water through them. I alway add a clear plastic filter from wal-mart to my trucks so I can see if the gas is flowing when it starts to act up... also could be a fuel pump going south on ya if it was a carb it should do it all the time also could be vapor locking

 

Moved to proper forum.