I just installed an on board A/F monitor and found that not matter what the ratio will not go below 14:1, even wide open. Does anyone know of a way to remap or chip the Tundra? Thanks.

No way to change it as far as I know. 14.7:1 is what is known as stochiometric fuel ratio. It is the ratio that allows the cleanest emissions while still allowing for the best driveability. Kind of a give and take.