My 05 Suburban 8.1L runs out of gas when the gas gauge still shows 1/4 tank. I know the 2500 series holds 37.5 gallons....So, I'll put 2 gallons in it..drive it to the gas station to fill up and it only takes another 24 gallons..26 total......Is it possible the pump in the 2nd small gas tank (11.5 gal) needs replaced?
Any info would be helpful.
Thanks in advance,
Greg

 

I'd check the fuse and relay for the 2nd tank fuel pump before replacing the pump.