What is wrong with it?

[lionheart21]

I have a 1995 Chevrolet K1500 with a 350 in it. It is the original engine with 150,000 miles on it. For the past few months I have been getting about 11-12 mpg with it, and when I bought it 2 years ago I got around 17 mpg. I was wondering if anyone would know what the problem would be as to why I am getting such bad gas mileage.

[jwokmuba2]

have you tried a tune up at all, air filter, sparkplugs and wires, fuel filter, if that doesnt work check your temp guage if your truck is not heating up properly your thermostate could be stuck open which would make the moter put more feul into the intake to try to heat up the motor