well it is what I suspected ! the dealership was trying to screw you out of your hard earned money . needing more testing at the dealership means get the anal lube out.
the tahoe fuel tank drop sucks. If you had fuel squirting all over you best get someone who knows what the proceedure is.
I don't want you to get burned up!
on pumps using your vin # you can get the correct ac delco or delphi fuel pump for around 200.oo....
with the pressure around 50 psi this is how the engine runs. sometimes just enough, sometimes not. shortly this will fall more and you will be stuck.
siphon the fuel out into a 5 gallon container. then place in your other vehicle. when done replacing the pump install the 5 gallons in the tank and see how the pressures look.
with the fuel at 1/8 indication the tank should be 50 lbs. 8lbs/gallon.
the fuel pump is re-designed so the connectors to the pump assy will need be soldered and sealed to adapt to the new style pump. unless this was done before .
DO NOT USE AIRTEX EVEN IF IT IS OFFERED FOR FREE !