My 88 wrangler gets the worst gas mileage. It is mostly stock with the exception of a pacesetter header, weber carb (with adjustable fuel pressure regulator), and tires about 30" in diameter. Last time I got gas it was only getting 10 mpg. It seems like it used to get better mileage, but I don't know. It also seems like if I drive a certain speed, like around 55-60 mph, that you can almost see the gas gauge go down. At first I thought it was the gauge, but not since I calculated my mileage to be only 10 mpg. The Jeep has about 110,000 miles on it. Is it just the nature of an old Jeep, or can I fix it? By the way, the Jeep has stock axles and ratio and a 6 cylinder w/ a 5 speed. Help!!