What is the gas mileage for a 2002 blazer with the 4.3 4+4 4 speed automatic

When new the car was supposed to achieve 22MPG on the freeway and 17MPG city, but consider since the car is 15 years old it really depends on your maintenance such as spark plugs, air filter and how clean your fuel system is. My best guess is your car gets about 18-19MPGs if you changed any of the above, once you change your engine oil with synthetic grade your MPGs should increase 1-2MPG

Check to see the miles per gallon yourself. Fill it up and mark down the mileage, run the tank of gas down, fill it up and record your mileage, and amount of gas it took in, then figure out what it is.

They average about 15-18 mpg