So I have a 2007 Lexus is350 and it was spitting codes p0172, p0175, and p0430. I went to the o2 sensors first and got a pack of upstream and downstream online, after replacing, the old ones looked pretty burnt out. After the new o2 sensors I got codes p0174 and p2179, Both for bank 2 but it seems bank 1 is fixed. I cleared the codes thinking maybe the o2 sensor was reading lean because it was new and needed time to adjust from rich. Once again after starting the car and letting it run, the two codes came again with a third code, p0300. Online it says that the misfiring can be caused by the previous codes, Most likely a bad o2 sensor, or fuel injector, spark plug, MAF? but it’s all a confusing rabbit hole and I’m still new at DIY diagnostics. Some info or help would be amazing.

1st scan

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I have no clue about your problem specifically (sorry).

I can tell you that I problems with codes saying my car was too rich, and also ones about too lean.

The dealer replaced one of the fuel injectors, and they replaced or repaired the wiring harness to that fuel injector.

As part of the work, they used new gaskets when the put everything back together.

I then got some more codes about being too rich, and the dealer cleaned the mass-air-flow sensor.

Since then, it's been good. Sorry that I can't be more specific to your problem, but I figured maybe it could help *some*. Good luck. You may need to take it to a mechanic who can troubleshoot and diagnose your issue.