Hello Everyone,

I come here often for answers so I figured I would join the chat! Anyways I have a 2009 chevy Aveo LT. Well about 3k miles ago I hit my 100,000 mark. Shortly after things starting going downhill, I just recently replaced all my tires, the spark plus, ignition coil, and both 02 sensors. I only changed the 02 sensors because that's what was coding, the car started bucking and revving to 4000RPM but wont accelerate over 60-65 MPH, if I am going up a hill it actually starts slowing down. So I tName:  Codes.jpg
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Well yesterday the check engine light came back on and I was able to get the codes. P0420 and P0641 both came up. P0240 said "pending" and P0641 said "confirmed". I am not sure what that meant but I read a few places and have mixed signals.

I guess my questions is can one code cause the other and if so would it be a bad catalytic converter or a circuit somewhere? I've learned a lot about doing it myself since I am a single mom and a repair man is most of the time out of budget. Any suggestions?