Saturn L-200 Poor Mileage - 2003 With 86,000 Miles

Within the past few months my average mileage has decreased from an average around 26 mpg to 22 mpg. Check engine light is never on and have recently had the fuel injection cleaned. Also had a new crank angle sensor as well as fuel pump installed due to stalling and starting problems during the summer.

My driving habits have not changed (very conservative) and the only other thing that was done was to replace the original Firestone Affinity tires with Goodrich TA’s.

Spark plugs were checked by mechanic prior to them doing the fuel injection cleaning and they were in good shape, so am completely at a loss about regaining the lost mileage. Any thoughts would be helpful.

If it’s never been done, bring the vehicle in and ask that the thermostat be replaced. A partially stuck open thermostat can cause a reduction in fuel mileage.


Has the weather gotten colder where you are in the last few months?

It could be simply the new tires combined with the change in weather. 4 mpg isn’t a huge drop. By the way, have you checked the air pressure in the new tires?

The Goodrich TA’s likely have a higher rolling resistance vs prior tires translating maybe to a 1 MPG loss. Winter temperatures and fuel account for maybe 1-2 MPG. Also have you checked your air pressure?

I would sway away from mechanical reasons myself.