I have a 94 f150
4.9 auto dual tanks
I haven't owned this truck for very long. There for several weeks it ran good.
Then, it started having trouble.
The heat here is very hot and humid. So i drive to town, about 20 miles, the
Truck runs great.
Then on my return trip home, it starts acting up...
It doesnt have any power then it just dies.
It will restart, then just dies. No power. None
I was afraid of it getting hot. Because the fan clutch was bad.
So i chamged it. It didn't solve the problem.
I had a freind tell me he thinks its vapor locking. I dont understand what hes talking about. Thx, for reading my thread......greg

 

Next time it happens, unscrew the fuel tank cap and see if it runs better. When you remove the fuel cap and it makes a huge hissing sound, you've got a vapor line plugged.

You might have a vacuum leak as well and that can be easily found by spraying carb and choke cleaner around vapor lines and connections while the truck is running. If the idle increases when you spray a hose, you have a hose or connection that is cracked and needs to be replaced.

 

I tried the gas cap thing, no whoosh or vacuum buildup in tank.
It tends to cough back into the intake to when it looses power.
How do you check a evap line for stoppage? Also could this be electronic?

 

No trouble codes? Dirty MAF sensor. The MAF is .

 

Might have an egr port clogged or hose cracked.

 

What do you mean by "cough back into the intake"?
I would check the EGR valve and vacuum, they seem to be popular issues with these trucks.

 

Well I am also thinking that you have vapor locking problem but if you checked that thing then I suggest you to visit some expert because maybe applying ideas on truck lead you more trouble. Its better to spend some bucks and fix it by some mechanic shop. Good Luck