I agree. I'm thinking it may be an injector leaking. I was having the 1/4 tank returnless fuel pump issue and had removed the pump several times in attemps to clean the sock filter and remove the disk screen, which didn't help, so I installed the fsvt pump. During these removals the fuel pressure has been very low. I'm not sure how low because my pressure gauge needs a new seal so I have not bothered with putting it on to check for leak down while the key is off. I remember changing the fuel filter a couple of years ago and the pressure was unbelievable. I thought it was never going to stop spraying!
Is there a way I could use my scanner to determine if an injector is leaking? I already have the manual that Tony linked for me. (Thanks Tony) I believe there is also a manual that is more detailed for around $100 which I don't have just laying around, my kids beat me to it!
I have replaced the lower bank one O2 sensor, still get PO172, so I switched it out with bank two's lower sensor, and I still get PO172.
