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2007 Chevrolet TrailBlazer- Mileage drop

My gas mileage has dropped by 2 mpg. Usually get 16 now is 14. Any suggestions from other owners on how to improve would be appreciated. It has about 122k for mileage

I would suggest you need a new thermostat. It is open a bit and not warming up the truck quickly enough.

That is, unless you just got a new set of tires and noticed this drop. Then the mileage drop is likely a fault of the tires.

If you are just doing short trips, and with it being colder out, your engine isn’t running long enough to get up to operating temperature.

y’know, it just cold here and i noticed the heater doesnt seem to be as warm which would indicate a thermostat problem too right. Is it difficult to replace?

BTW no new tires

Not really…

Either thermostat is opening too quick or it is simply the switch to winter blend gas which lowers your mileage . If the stat is bad though usually you will get a CEL with a P0128 code set .

Depending on where you live, ours is 10% ethanol year round.

Thanks much!

My trailblazer set a CEL for running too cool indicating I needed to replace the thermostat, I would find if your car is the same before worrying about the thermostat. I lost 2 mpg after new tires probably 8 years ago and never got it back. Asked a mechanic bud to check, he found nothing except a leaking fuel pressure regulator, and it did not help gas mileage. New plugs and filters did not help either. I’ve thought about doing an o2 sensor just for kicks, but have not gotten around to it.

Thanks for your input

Winter blend vs summer blend has nothing to do with Ethanol concentration