2012 Suburban Misfire #5 drama

[Keiterburb]

I don’t know a lot but shouldn’t both banks look similar? Is cylinder 5 on bank 1?

Yes, but from what I gather so far in my studies The downstream sensor 2 should look much flatter…small adjustments over time. According to my graphs Bank 2 appears worse than bank one with the misfire on#5

 

[Dustin Jackson]

@Keiterburb My interpretation of those photos is that bank 2 is performing better, the consistent bumps is good, bank 1 readings are not consistent.

For fun I consulted ChatGPT and it agreed:

 

[Dustin Jackson]

@Keiterburb Can you shoot some pictures of your fuel trims?

 

[Keiterburb]

@Keiterburb Can you shoot some pictures of your fuel trims?

One was at idle following the warm up drive, erratic one was while driving throttle moving

 

[Dustin Jackson]

@Keiterburb Bank 1 is running slightly rich. This could be from a bad MAF or O2 sensor, or maybe the intake lobe on the cam is damaged not allowing the valve to open enough.

Might be worth cleaning your MAF and swapping your bank 1 and bank 2 upstream O2 sensors to see if the problem persists but my theory is the O2 sensor and fuel trim readings are the result of the #5 misfire and not the cause.

We are running down the possibilities