P0455 where is problem sierra 2007 new

Question

What the parts change for this problem.o2 changed rear and front code p0171 and p0174

Answer 1

p0171 and p0174 is most likely and intake leak or a dirty mass air flow sensor. The MAF (Mass Air Flow) Sensor is dirty or faulty. if you used a K&N "oiled" air filters may cause the MAF to become dirty if the filter is over-oiled.

try to clean the mass air flow sensor with mass air flow sensor cleaner and check for intake leaks after