rough idling and lack of power
recently purchased a rx300 with 96k on it. Shortly after CEL came on. PO171. Cleaned MAF and then replaced when the light was still on. Ran great for couple weeks with light coming on and off periodically. Now CEL is on and P0171 and PO172 is shooting out and the car is idling rough and hardly any power. I was thinking about replacing the bank 1 sensor 1 which would be the A/F sensor and replacing bank 1 sensor 2 which would be the O2 located underneath driver seat behind catalytic converter. Would this be a step in the right direction. I did notice black residue on end of tail pipe but never saw black smoke come out. Bottom line is I need HELP!