2007 Mazda Mazda3 burning more gas than usual

Why my car is burning more gas than usual?

Maybe a bad thermostat?

Would you elaborate a tiny bit more? How are you measuring this? Have you changed anything of the car recently? New tires? How many miles on the car? When did you notice this? Stuff like that.

Check that the tires are inflated to the proper pounds would be my first guess.


Two things to check.

Either a bad thermostat, or a bad coolant temp sensor for the computer.

If the engine doesn’t come up to full operating temperature, or if the computer thinks the engine doesn’t come up to full operating temperature, the engine will use more fuel.


If the engine coolant temperature gauge is reading lower than it was when the mpgs were ok, probably the thermostat. Wouldn’t be at all unusual for a thermostat to warp a little and lose its seal at the 11 year mark. Problems with a coolant temp sensor is possible, but not as common.


This vehicle has three coolant temp sensors.

One for the cooling fans, one for the gauge/light, and one for the computer.


Benny32 had this thread and vague question transferred from carcomplaints 2 days ago. He has not provided why he thinks the fuel mileage is less or how he checks it. Why even bother with speculations?

Most likely it would be the one for the computer, if that’s what’s causing the mpg problem. Like I say above, imo more likely the problem (if there is one) is the thermostat. My Corolla has 5 coolant temp sensors, one for the fan, one for the gauge, one for the cold start injector, one for the purge valve, and one for the computer.