Another Dreaded PO300 Thread

[SonicVQ]

Since you have an OBD scanner, you could use OBDFusion and look at the mode $06 misfire counters.
It is shown as part of OBDFusion's wonderful diagnostic report.

This might give you an idea which cylinder has the highest count and that tells you which bank.

Also look at the fuel trims.
For each bank, add the short term and long term together to get the TOTAL fuel trim. This is how much the ECU is adding/removing fuel from the fueling calculations.
Negative is reducing fuel, positive is adding fuel.
Generally acceptable TOTAL fuel trims are -15 to +15%

The next time the CEL is turned on, run the diagnostic report and it will capture the freeze frame data, and that show the conditions when the misfire happened. This is very helpful when troubleshooting!

If you want to post the full report (just blank out your VIN) I will have a look at it and give my thoughts.