Poor MPG

[SML]

This is my second Mazda5 and I know MPG is not their strong suit. Normally, in my previous car I would get about 20 around town depending on conditions etc. My last measured MPG has been about a 18 with a low of 17.75. The conditions are right for poor MPG with winter, warm ups, ethanol gas etc but I never saw this low in the last one.

I don’t show any codes but did replace the thermostat recently and that code did not come back.

Any thoughts?

 

[theblooms]

How many miles since you last changed the plugs (and did you use the correct plugs?)

 

[SML]

I bought the care with about 50k and it has about 55k now. I doubt they were changed but they may have been. However, the mileage was better when I first started paying attention.