Originally Posted by viali8
I have an 87 325 with 216,xxx miles. just recently i have a seen a drastic drop in my gas milage. When i first bought the car i was getting about 260-270 miles per tank in the city and 340-350 on the highway. Now i am only getting about 260 miles to the tank on the highway.
I changed the fuel filter about 40,000 miles ago. What could it be that is giving me such poor gas milage? Also i bought the car with 177,xxx miles but never changed the O 2 sensor. Could that be the problem?
Has anyone had the same problem before and what did u do to fix it? Oh also i am driving with snow tires on the back, but i doubt that makes not much of a difference.
It all depends on if you have noticed a performance change with the drop in your mpg. The coolant temp sensor, O2 sensor, air temp sensor (built into your air flow meter) the airflow meter itself all heavily effect the MPG (and running quality) of your car. Along with spark plugs, weak conducting wires, wore out cap and rotor. Also don't rule out failing wheel bearings and dragging breaks as well. Just to skim the surface.
The most common to drop the MPG of most any car is the O2 sensor, it should be swapped out about every other timing belt change if you change it at the 30,000 mile marker.