I realized a 3-4 mpg improvement when I finally figured out what Tier 1 gasolines are.
Look up the stations in your area. I tried Turkey Hill gas for the first time a couple weeks ago and got 3 mpg more.
I was surprised Sunoco was not on the list. Next tank I put Sunoco back in. MPG went back down. Ran that out and put the turkey Hill back in. Car even runs better on Tier 1. Learn something new every day
TOP TIER Gasoline Retailers:
QuikTrip
Chevron
Texaco
MFA
Oil Co.
Conoco
Phillips 66
76
Entec Stations
Shell
The Somerset Refinery, Inc.
Kwik Trip / Kwik Star
Aloha Petroleum
Tri-Par
Oil Co.
Turkey Hill Minit Markets
Mileage Stations
Chevron Canada
Shell Canada
Petro-Canada
Sunoco Canada