2007 tahoe tuning economy

this is my first vehicle ive ever tuned and its still stock, the only reason for buying a tuner is because i had an issue with the virtual flex fuel sensor and it caused really poor fuel economy. now that thats fixed i was trying to squeeze a few more mpg out of it and i think im in over my head, any insite would be appreciated.

heres what ive adjusted,

ive turned off p0420 and p0430 and cot as i dont have cats. i also turned off Flex Fuel

Attachment 161437

i have slightly adjusted DFCO, i turned off DOD, i adjusted the "Mode vs. Airflow", and the bank 1 and 2 voltages to try and make a lean cruise condition while cruising.