ok so i have a 96 f150 4.9l i currently have the po171 and po174 i rebuilt the motor every gasket for the oil pan up i got new o2 sensors and a new cats which it needed i smoked the vacume lines and had no smoke comming from the lines i only passed emissions by making a mixture of 93 and 100 octane to make 96 octane and the light went off till i ran out of gas so my question is what did i miss and what do i need to do to get rid of these damn codes

 

Could be a bad or dirty MAF sensor since both O2 sensors indicate lean. Low fuel pressure can also be a root cause.