How much gas does a 1989 GMC Jimmy use?

[Andrew (6 pack)]

Lets say I have a full tank, and I drive a half hour. After that half hour, how much gas should I still have? My gas guage doesn't work, it always tells me I have a full tank.

 

[QuadFreak400ex]

Well it depends on how you drive. If you Romp on it a lot and like to here your exhaust compared to if you drive like a grandma will make a huge difference.