MY 03 FORD EXPEDITION XLT CHECK ENGINE SOON LIGHT IS ON

I have changed every sensor on the motor and i had 2 of
the cadilac covertors changed and the other 2 elimanated
since they were really needed i have been fighting with
this truck for about 4 or5years now i really cant afford
another suv right now but it keeps throwing the bank 1
and bank 2 to lean and the egr also i have changed both
upstream sensors and both down stream i have changed
the egr 4 times i took it to a place that has the machine
that pin points exactly the issue and the guy told meto run
higher octain gas and it should solve it well i have tried
that and ive tried putting a octain booster in it but the
check engine light is still on i have even tried clamping the
battery terminals together cuz the guy said it would reset
the computer well i drove it maybe 10 miles and the light
came back on i dont know what else to do i really need my
truck i have 7 kids and my truck is all i have to take them
to the doctor and etc...if anybody can help me figure
something else please help