Could changing the thermostat help me get better gas mileage?? I'm getting 2 MPG better now that I have a new thermostat. Same roads, same driving style and definitely 2 MPG better.

 

Was the old one broke?

 

If the old one was in poor condition, yes it would help improve MPG. Thermostat keeps the engine at the normal/correct operating temp and if it allows the engine to run colder than it should, the engine would require more fuel. Note, though, that this is a general theory and this may not apply to certain cases.


JPN

 

Yes, it had been broken since I bought the car in January. The gauge would barely rise above the first line.
I think I proved the theory!!!

 

Yes it could, as the engine is getting up to proper operating temperature now

 

I too think you did!!!


JPN

 

There you have it.

The coolant temperature sensor would have been telling the EMS the engine was not up to normal operational temperature and the EMS would have then automatically made the fuel mixtureto the engine richer to compensate.

Basically you have been driving your car around with the old equivalent of the 'choke' always being on.