I have a 2008 300 with the 2.7L V6. I keep getting codes P1128 and P1129 with additional information Freeze frame DTC P1128. I can clear the codes and for a while things are good. Then without warning the car will 'jerk' while driving and shortly after the check engine light will come on and these codes will be back. The engine will also occasionally stall while stopped both in park and drive. I am able to restart right away with no issues. The stalling by itself doesn't throw any codes or the check engine light. I've searched these codes and I'm seeing a lot of different suggestions without a definite fix or even a process to troubleshoot. I've seen everything from re-flashing the ECM, to changing out different sensors, to looking for worn wires.

Can someone please give man an idea of what items I should check and in what order?

Thanks

 

The dtc's indicate neither bank was able to enter closed loop operation where the air/fuel mix is determined by the sensors. Staying in open loop (typically when engine is cold and more fuel is needed) could cause stalling when the engine is warm/hot due to an extremely rich air/fuel mixture. What did the freeze frame data show?

It could be anything from corroded connectors, missing ground straps to failing O2 sensors. I would rule out O2 sensors at this time as it would be unusual for both to fail at the same time. I would look at the wiring first but this is simply a guess on my part. If you scanner is capable, you may be able to see the live O2 readings and short-term and long-term fuel trims to determine if they make sense. Again, I do not suspect the O2 sensors themselves but may be able to point to an wiring/corrosion issue.

 

Just an FYI for those looking at this post. It wasn't a bad sensor anywhere. As it turns out it was a loose EGR tube from the valve to the intake plenum. Not only was the seal gone at the plenum, but the screws were loose where the flange holds it to the EGR valve. Fixed those and the codes haven't come back.

 

Good on you Speedy for closing out this issue with us. So few do so unprompted..