Need some help figuring my issue out 09 aveo lt with lxv engine 1.6L. i have p0301 and p0420 code poor acceleration horrible fuel mileage and ac being on makes it run worse but I think that is due to running off 3 cylinders. Fixed other issues just the 2 codes remain. I changed plugs and coils air intake hose which was ripped cleaned throttle plate,cam sensors and crank sensor changed downstream 02 sensor w a throwing code until replaced it with OEM ac delco sensor. 105xxx mileage. Idk what else to check thought about running cataclean through or removing front 02 sensor from manifold as I don't have tons of money right now.. PLEASE HELP!!!