Fluctuating Gas Mileage
Last month I purchased a 1990 Oldsmobile Eighty Eight 2 Door with 54,000 miles. With the tank full, on my first drive around Phoenix with the a/c on half the time and driving normally, I got 13mpg. Then, I drive on the highway at a constant speed of 55mph (cruise control on) for 80 miles with the a/c off and get 20mpg. Then, I drove around Phoenx for 80 miles with no air conditioning and driving like a grandma, staying at the speed limit and at a constant speed as much as possible. I got 20mpg. Unbelievable. First, I get 13mpg in city driving with the a/c on half the time and driving normally, then 20mpg on the highway driving for 80 miles at a constant speed of 55mph cruise control, and now 20mpg around town driving like a grandma with no a/c. I'm totally stumped now. What's going on with this car? I'm not making this up. I'm just perplexed. The only think I can think of is that this car is "breathing and opening up more. Maybe the highway drive "cleaned the car out." The car only has 54,000 original miles.The man I bought it from was in his late 80's who only drove in town to the store and church.