My Olds Bravada is getting really poor gas mileage around town all of a sudden. Like 13.8 mpg which is REALLY bad. I looked at the air filter and it looks OK although it hasn't been changed in a while. Also, the check engine light isn't coming on.
Does anyone have any ideas? I just went on a trip and was getting 19.4 mpg, which isn't too bad, although on flat highways, I can get around 21-22.
Thanks