Can anyone tell me what could make gas mileage go down on a 2004 Impala Ls? I only get about 210 miles off a full tank before the gas light comes on. If I am not mistaking that is only averaging 12 mpg in the city. I do not really drive the highway often so I am not sure about that. Also when my gage reads 1/2 tank, 50 miles later the gas light comes on. I got the car in March and I am not sure about the upkeep. It runs great with no problems except for needing wheel bearings and tires. Any suggestions please?

 

air filter,fuel filter, plugs, wires, pcv filter, throttle body cleaner, fuel injector cleaner, oil change, alignment, loose front end, soft tires, seized calipers, emergency brake on partially\seized

So many things can affect MPG's, the biggest thing would be to take it in for a tune-up and just have everything checked over

 

like he said....
are you dividing the # of miles by the number of gallons pumped in? (do not divide by the size of the tank)