I just purchased a 2000 Blazer that has a bad fuel gauge. The gauge reads full all of the time or at least that is what the previous owner told me. This morning (the morning after purchase) the vehicle would not start. After a time I decided to add some fuel in case it was out of gas. After doing so it fired up immediately. I went to the gas station and tried to put more gas in the tank but after about 2 gallons the tank began to overflow. Since I really have no idea how much fuel was in the tank I am concerned there is another reason the tank will not take the fuel. Is this a possibility or is the tank just full. How can I tell

 

Could be the evap not working properly. Try filling a little at a time, if you can get more in it then it's probably just gas fumes building up in the tank causing it to not fill correctly. Check your evap solenoid.