P1135, P0125 codes returned

Question

Replaced both A/F sensors, CEL back P1133, P1135 (Bank 1 Sensor 1) Also gave me PO125, replaced the A/F sensor again (bank 1 Sensor 1) cleared codes, only getting the PO125 & P1135 now, how do I correct??

Answer 1

The first thing to do is check the ECM. Did you use oem brand oxygen sensors? 

I would replace the fuel filter as a second step if the ecm is good and check for intake and exhaust leaks.

Maybe clean the EGR and its piping and use a good fuel system cleaner like BG 44k or 3M, use it with 91 octane from Shell (issue might be injector related like a clogged injector) and maybe do an intake flush to decarb the engine