Ok, I've got a good one. My step son ran out of gas, while trying to sneak some from us he grabbed the wrong gas can and put about a gallon of weed killer in the tank and ran it for a short time (10-15min). We have pumped what we think is everything out of the tank and have replaced the fuel filter. However the truck will start but it won't stay running unless you continously pump the gas.

Any suggestions?

 

that is a good one and a new one. i woul d just pump everything out like you said you did then fill the tank to the top with good clean gas. also if possible, since its a 84 it should have the manual fuel pump on the side of the engine, disconnect the line going into the carburetor put a rubber hose or something on that line so you can get it into a clear container then just crank the engine til it sprays out all that crap and the gas looks clean then hook the line back up to the carburetor. thats what ive always done when working on cars that sat for a very long time or after putting a gas engine into a diesel truck, flush the tank and the lines.

if you dont want to go through all that, you might be able to just fill the tank and let it run it should dilute it enough to make it run good