2003 Chevy Suburban Possible fuel pump problem

I have 2 thoughts.

1, the fuel gauge sending unit is incorrect and you really are out of gas when the gauge reads 1/4.
or
2, Something in the pump and sending unit is cracked or a seal is bad, allowing the pump to suck air if the fuel level gets too low and the pump is cavitating.

begs the questions...

(1) how can I tell the capacity of my fuel tank in order to check it?

and

(2) is there any way to check out the fuel pump problem? I've heard that fuel pump repairs are major-league expensive.

1
Drive it until it dies because it ran out of gas, note where the gas gauge is and then note how many gallons it takes to fill it up.
You can’t trust what the factory says a tank capacity is.
Say a tank will hold 20 gallons if it was bone dry.
But it can only use about 18 gallons of fuel because the other 2 gallons are below the point where the fuel pump can suck it up from.

2
Without visually checking things out, you could do a fuel pressure test with a gauge the next time the problem happens. Before and after you add the extra gallons it takes to get it started. so you have some hard numbers to prove what is going on.

Fuel pump replacement isn’t too bad. But it can be time consuming.
You have to drop the tank, disconnect what feels like a million hoses that are all in the worst possible spot and then replace the pump inside the tank.

You want the tank to be as empty as possible, 30 gallons of fuel is heavy.

Did you find a fix to your problem? I have the same problem, I have a 2003 4wd flexfuel, when I get down to a 1/4 tank and let it sit for a few hours it won't start until I put a few gallons in, I know the gauge is correct, I have gone straight to fill up and know the gauge is correct..

my most recent problem is it cuts off while driving and I have to pull over and wait a few minutes before it will start again... I'm going to try a fuel filter replacement first

We have a 2002 suburban we bought brand new and did not have any issues until about 2005, and now it consistently does the same thing yours does, at 1/4 tank level, if you stop the engine it will not start. We can put a little as a half gallon of gas it it starts right up. We too have gone directly to the station and confirmed the gage reads correctly for the amount of gas we fill it up with. Has any one found the real problem?

We too keep getting direction from mechanics to change the fuel pump, but then they say that means the fuel sending unit probably will have to be changed as well all for about $1500. Otherwise the truck has been great!