PO171 Bank 1 fault on '05 Bonneville SE
The guys at Advance said I needed to replace the O2 sensor on bank 1, but several websites said a dirty MAF was the most likely culprit. The car runs fine. So I cleaned the MAF and reset the codes, but it recurred after a few minutes of idleing.
What would you recommend as my next step? Replace the MAF, replace the O2 sensor, or what? Websites seem to suggest that this could also be a vacume issue.
BTW, I don't know if it is related, but I also have an intermittent AC problem where the system won't come on at all. The panel lights up and I can hear the compressor come on, but the fan doesn't blow. Then it will start running randomly as I am driving. Very strange.