Is there a reason why I might be getting bad city gas mileage. I calced it out to be about 18mpg in the city, but then 35 mpg on the highway. Is some sensor going biserk for city driving that's making my mileage stink?

1998 Mazda Protege LX Auto 1.5L V4

 

the main cause for low city mileage is loss of horsepower. in the city, you need the extra power to get from light to light, whereas, on the highway, you don't need it so much because you are already accelerated and in OD. also, auto trannys tend to get lower city mileage because the autos slip to switch smoothly from gear to gear and to get moving from a stop. i would just go over a basic tune up and see where that puts you.