Water in gas tank or something else?

[hatzie]

Originally Posted by 1979 GMC Sierra

Thanks a lot guys for all the info and insights! I appreciate it. So far, indications are that it was what I suspected, water in the tank, making it a fuel problem as a lot of you suggested. I checked the gas filter and it was hard and you could barely blow through it. Had to clean it up (bought a couple new ones now, but wanted to see if the truck would run first), and I could then blow through it better.

Also, was able to siphon most of the gas out with a hose (was hard to get the hose into the tank, worked at it for awhile) and there was a bit of water at the bottom of each pale we used. So I had water in the tank, got bad gas somewhere then. Put the gas back in the tank after separating it from the water. But I don't know if I got all the water out of the tank cause you can't see how the siphon hose is sitting inside the tank. I started the truck and let it idle for a half hour, then I drove the truck for awhile and there was no issues. Dumped some more water eliminater/de-icer into the tank today.

I'm thinking of buying some 99% Isopropyl, like hatzie mentioned, and dumping it it to try and clear up any water I missed. Any idea how much I should or could dump in?

It comes in 12oz bottles. You're supposed to use 12oz in roughly every 10 gallons of fuel. I'd dump three bottles in a heavily contaminated tank... That's 36oz of isopropyl in the tank... then fill it all the way up from a high traffic fuel station that moves lots of fuel.
If you're close to a Pilot or Flying J or TA or Williams or similar truckstop get fuel from them. Their fuel doesn't stick around long enough to get condensation and the gubmint goons ride them pretty hard on inspections and the like.