Engine Check Light Codes 25,26,71,28

[nbaballer1988]

my Es 300 94 lexus was acting up earlier this month and i took it for a diagonstic and they told me it was more likely the timimg belt was off track. my mechanic saw the timming belt was the problem and he fixed it but now the light is still on i took it back to pepboys for another scan and the codes that came up was 25- air fuel ratio 26-air fuel ratio lean 71-egr malfuntion and 28- 02 sensor circuit. could any one tell me what i need to do?