Originally Posted by cmiovino
I originally bout the car with the stage 2 93 oct map, but noticed some pinging when testing some WOT runs. I switched to the 91 oct map and have continued to use 93 oct fuel... the pinging has completely gone away, however, my gas milage has dropped to 16-18 MPG over the past 2-3 months I've been tracking it. I used to get 19-22 with the same exact driving habits and route.
Could the tune be effecting my results, or can I solely blame this on winter gas and cold weather?
2004 WRX, Cobb turboback and SF intake
First thing to do would be to get a data log (if you can do so safely) as described in the video below (if you have a version 2 AccessPORT). The version 2 AccessPORT also has newer maps (v310) that you want to make sure you are running (vs. the old v300 maps). You can find these maps in the maps section at cobbtuning.com. Regardless, the 91 octane map is not going to get worse gas mileage than the 93 map, so it is likely just colder temps and/or winter gas that is effecting your mileage. But, a data log can potentially tell us if there's any mechanical issue with your car that might be effecting mileage. You can use google docs to put up your log and then post a link. Be sure to state the approximate number of miles you've driven since you last reflash a map or reset the ECU.