How many miles should I get on a full tank of gas.Its a 2002 Chevy Tahoe Lt

Fill it up (Take note of how many gallons) Have a 5 gallon gas can strapped ie back (filled) and drive until it runs out , and you'll have your answer ,I think.?

mileage varies,highway,around town,heavy foot, sending unit in fuel tank most likely bad.if it is tahoe 1500 and 5.3L, engine 4WD,when it was new,14mpg city,17mpg highway.tank size approx. 26gal tank