Quote Originally Posted by Fast355 View Post
Funny thing, my grandmothers '03 Alero 3.4 that is driven only in the city increased its MPG over 20% with a tune, running disabled EGR.
There's got to be some differences here we are not looking at like:
1. Elevation? Greg and I are at 2000 feet.
2. Tempreture? We rarely hit 90 in summer. Cooler all year then you.
3. Fuel? I think we've had this discussion before but is E fuel there's the same as here? Refiners are close to texas so is fuel fresher? It's old by the time it gets here? I really don't know where our fuel comes from.

Fuel: In Closed Loop my WB reads AFR of 13.8. E10 is supposed to be 14.1, do we have more E in out fuel? IIRC last summer I did some MPG data and the expense on Non Ethanol was well worth it.