My front gas tank almost always refuses to take gas. If I put the pump in the tank and start the flow, it acts like it is full and spits the gas back. It does this almost all the time, which is pretty annoying cuz it makes the front tank unusable. On rare occasions, if i pump the gas very slowly, it will take the gas and function normally. It seems to work with only certain pumps and only at certain gas stations. so any suggestions are appreciated. its a 1994 f150 with an automatic tranny, 4.9L straight six.

 

I would suggest looking at the filler neck from under the truck to see of any obvious obstructions, next if you have one of those inspection cameras with the 3 foot lead ad see if you can see down the neck. If not then you'll have to drop the tank to do a thorough inspection. Hope that helps.