just bought a 1999 f150 4x4 4.6l and the check engine light was on so i stopped at auto zone and had them checked. the codes that came up were, P1151 lack of o2 switches bank 2 sensor 1,
P1152 lack of o2 switches bank 2 sensor 1- Rich,
P0136 Ho2s12 circuit condition (heated oxygen sensor bank 1 sensor 2,
P0043 EVAP (evaporative emission system) Purge/vent solenoid circuit Condition

 

Think you got 2 things going on. The O2 sensor codes could be from a broken or rubbed wiring harness [usually at the back of the motor going across the top of the tranny] and the EVAP code is for a bad purge valve.