Help!! 10 mpg on premium!!

[big_c_snow]

I have a major problem, and I hope someone can help me out here. I have a 1986 chevy 1/2 ton, 305, TH700R4, 3.73, and 29" tires. I am getting 10 miles per gallon, which is a combination of city and highway driving. It probably wouldn't be that bad, but I have to put 92+ octane in it, and it still pings under anything but very low throttle. I also live 30 miles from anywhere, and have one 18 gallon tank. 30 bucks every three days sucks when you work fast food. Anyway, I hope someone can help me with my fuel mileage problem. I drive it kind of like a 17 year old kid would, but i try to go easy on it and still get 10 mpg. I also lost to my friend in his Chrysler New Yorker, which was embarassing. Thanks for the help!