So I bought a 2.0l cobalt ss stage 3. The engine ended up blowing so I bought a new engine and is now stock besides the injen CAI. I called the guy because idk what PCM is in the car so idk if I'm running a stage 3 tune on a stock engine or if I was running the stage 3 engine on a stock PCM.

Anyway sometimes it drives perfect, has power and picks up great. Other times it will buck or feel like it's holding power back. Half the time it works and half the time it does this

I have switched out MAF, HO2S, throttle body from old engine and put on this one. I also bought brand new spark plugs

Codes are p0171 p0103 and p1133

 

P0103 Mass Air Flow (MAF) Sensor Circuit High Frequency -PCM
P0171 Fuel Trim System Lean -PCM
P1133 HO2S Insufficient Switching Sensor 1 -PCM

next time post the definition of the code or your post will be deleted

 

Thanks for the help lol