My 03 Denali yukon gas not reading correct. 2 years ago I had replace all the stepper motors behind the needles so I know the cluster is good. So basically I have 32 gallon tank half will be 16 gallons and a quarter will be 8. So on empty I put in 10 dollars and that gives me a quarter tank which is wrong. At 2.18 a gallon thats 4.5 gallons which should be between a quarter tank and empty. Could it be my level sensor in the fuel pump.

This has been a common complaint across multiple vehicles across multiple generations. Fuel tank shapes and fuel gauge behaviors vary greatly. Also, in later generations, it can be averaged out to reduce gauge movement. If gauge progression is smooth, and consistent (with itself, and not necessarily what you think it should be), it'* likely working as designed. If the gauge jumps around a lot (not to be confused with fuel slosh of earlier generations) all on its own, whether it be all the time, or when it hits a certain point, then there is likely an issue in need of addressing.

I do not believe you have an issue that requires addressing just yet, however if there is an issue, it could be either the cluster (again), sender, or wiring. Also remember too that GM gauges are notoriously inaccurate, even when working properly.

I understand what u r saying but of o put in 20 dollars that'* 9 gallons and the needle goes to half a tank I know that'* wrong and I know it should be between a quarter tank and half so I'm guessing maybe a new fuel pump should do the trick and also say if my needle for the gas gauge is bad how do I find out

A more accurate way to test the gauge/sender is with resistance.....

Disconnect the harness to the fuel level sender......then attach a 40 ohm resistor to the fuel level circuit(zero), 80(1/4), 120 (1/2), 160(3/4), 240(F).....

Those senders are famous for not being truly accurate......my truck gauge drops very slowly from F to 3/4.....3/4 to 1/4 drops much faster......1/4 to E slower.....

Thanks I'm a just replace the fuel pump and call it a day