Improved mpg from tstat?

[monterey]

Well I've been getting the tstat check engine for a while. (Everytime i drive off without warming the engine for 2 mins). My gas mileage was very poor (10 mpg) so i swapped out my spark plugs and got an additional 50 miles per tank. I then swapped out my tstat and sensor, after two tanks of gas i did not notice any increase in mpg. While my mpg is nowhere near what my coworker is getting, (He is getting 17 mpg whereas I'm only getting 13) I'm happy that I'm finally hitting 200 miles per tank.

The condition of my tstat was definitely defective. It had a lot of play and my sensor was coated. I actually should have changed my water pump after seeing what heat did to the tstat gasket. That plastic impeller is probably very brittle by now.

[JsL]

You get 13mpg now? Do you drive it like you stole or drive in constant stop-and-go traffic?

Seems very low for an average, have you checked for other codes?

I had a tstat code pending, changed it and didn't see a change in mpg.

[monterey]

Im in stop and go all day long

[msan]

I get 13 in mostly local driving

[deansbimmer]

We usually get 260-280 miles per tank in city traffic. Got a bit over 300 on our last road trip. In theory a defective thermostat or temp sensor that won't allow the engine to reach operating temp or enter closed loop dme operation will cause the engine will run rich. Fuel economy will suffer.