What size is my fuel tank?

[SquareRoot]

Being EFI, they really need to have some fuel in them for best pump life, and I suspect GM's rating of tanks was a little more conservative on the early EFI to account for it.
I went the opposite direction from SquareRoot on my wife's daily. She liked to run it lower than it should, to the point of me having to rescue her with a 5 gallon can a few times. With HPTuners, I adjusted it to read a couple gallons lower without her knowing, and we haven't had issues since. The speedometer is also a few MPH fast to help on the speeding tickets...

Smart guy. I set the clocks 10 minutes fast in my house and she's still late!

 

[hoagster]

Well thinking about your issue, I'll almost bet that either or both of your fuel hose's from the filler to the tank are done! I'm surprised the gas pump vent is allowing you to pump gas at all!

 

[BKING33]

If your spid label on glove box lid is legible, the code for a 40-gallon tank is NE2. If you don't have that code, then it's a 31 gallon.