I have a strange problem with my 54 3100 235. I thought it was a bad fuel pump. Now the new one is doing the same thing. I can drive it for long periods with no issue. Then, without warning it starts cutting out as if it is starving for gas. I have an electric booster pump that is capable of operating on it's own or to supplement a mechanical pump. I installed it to help prime the fuel line when the truck has been sitting for a while. I have the electric fuel pump on a toggle switch. When the truck starts cutting out, I can flip on the electric fuel and the engine will smooth out and I can keep going. If I do not turn on the electric fuel pump the engine will die. I can wait a few minutes and it will start back up. When I turn the electric fuel pump on, I can turn it off again after a minute and the truck keeps running fine until the next time it decides to cut out. If I leave the electric fuel pump running, the engine will go forever without cutting out. I am going to use the dreaded phrase. Could this be "vapor lock" and the electric fuel pump is powering through the issue?
