Code 43 means theres something wrong on the o2 circuit or fuel system, here are the possible problems.
o2 sensor
egr valve
fuel injectors
fuel injector resistor
fuel pump
fuel pressure regulatior

Check all these, make sure your o2 sensor wires aren't grounding or shorting out, run some fuel injector cleaner in case of clogged injectors. Those would be the things I would check first. Good luck, just ask if u need anymore help.