1990 Caravan, 2.5 turbo, automatic. If my 02 sensor was bad, wouldn't I get a code flashing when I check for one? The thing runs perfect, just gets lousy gas mileage. When I rebuilt the head 2 years ago, it got 24 mpg highway, and 18 in town. Now it only gets about 13, or 14 in town ,haven't been able to check highway lately. It still runs pretty strong, no problem breaking the tires loose from a dead stop by just stomping it. Cant find any vacuum leaks, recent tune up. Doesn't show any codes when I checked it. Any ideas?