Update
To start my last tank is the best yet 51.2mpg only 1 mpg better that my previous best but the current tank is looking better. The last tank got me 848.9mi so it is getting close to the 900mi mark
Here is what has changed in the last month:
Car rolled 200,000mi
Replaced temp sensor it died on me and kept fans on for two tanks
Changed t-stat w/hotter 195F
63% coolant + 6oz watter wetter
Oil changed 0w-40
Larger fuel filter eliminated fuel heater
Replaced Vacuum lines