Bank 2 rich, bank 1 runs fine,

[Ohhnulix]

My 02 4.0 sohc started throwing a code for a rich code on bank 2, but only bank 2, I’ve yet to find any sort of reason for it, as most issues should be for both banks, any recommendations?

 

[RonD]

You can get an Bluetooth OBD2 unit for under $20, like ELM327

If you have an OBD2 reader then hook it up and start engine
Engine has to be warmed up before O2 sensors can work
Select live data
And look at STFT bank 1 and 2
Drive it while you watch the STFTs
If both are showing "-" numbers then BOTH banks are effected, but only bank 2 has set the code so far, so not "running fine"

And check O2 sensor voltage sensor 1's, there are two sensor 1's, those are the upstream O2s
expected is 0.3 to 0.5volt, higher than 0.6v is Rich


And look at LTFT what's the number?
Usually a code is not set until -20 or +20 is reached

How old are the O2 sensors, they last 12 years, they run out of the chemical used to detect Oxygen, only sensor that actually can wear out and does

There are 3 injectors on each bank of a V6 engine, one could leak and would only cause an issue(rich) on that bank, unlikely problem but you ask