Fuel pressure

It will kick the light on (EVAP Large Leak). Did the fuel pressure drop with the cap off? Also, have you ever checked pressure before the filter? One last question. I have one other thought. Are you able to check voltage to the pump when it loses pressure? I wonder if the voltage is dropping and the pump is slowing down. Based on what you have already done, I am assuming you have a fairly good knowledge base for this repair. But I have to ask if you have a good ground for the pump.

P0153 is oxygen sensor bank 2 sensor 1

has nothing to do with the fuel pressure regulator.

What I would do is try a new o2 sensor or switch it with the one from bank 1 if it switches to bank 1 then the sensor is bad.

Yes, rich mixture will damage the catalytic converter, but how do you know you have a rich mixture?

Code p0153 its an oxygen sensor slow response on bank 2 sensor 1
you need to update your book
fuel pressure is about right

No, you can't assume anything like that. Lean fuel mixture would lead to lean misfire and poor mileage also. If your 0/2s aren't setting rich codes, it would be wrong to assume that.

Guarantee you your o2 sensor is to blame, your fuel pressure is just fine.

Regardless if it has flexfuel, it still maintains the same pressure, between 60 and 65 psi (KOEO).

Let me know if you have other questions.

Joe

No, you seem to be correct about it being the regulator. Kinda unusual though.

Are you sure you can trust the gauge?

60-65 psi Here is a guide to help you get the pressure reading.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Please let us know if you need anything else to get the problem fixed.

Cheers

Yes, it shows the increase but if that gauge was off by as little as 10PSI, that test would translate to no problem at all. That's all I'm saying. If you trust the gauge, then fine, replace the regulator.