I know this is an old post but to all future spectators know that this is partly true but overall WRONG in context to this post. A 99% reading for the (after) catalytic converter's o2 sensor (#2) is correct meaning the cat is doing its job and releasing 99% of oxygen and holding back pollution. If it was 99% on or sensor (#1) then that would be a problem.Key on idling it should be 51psi
The STFT means that:
Your "short term fuel trim" is adding 99.9% fuel in order to get the proper air/fuel ratio.. essentially telling you that your ish is WAAYYY lean bruh.
LTFT (long term fuel trim) is altered if your STFT stays hi/low long enough... meaning that if you're at 99% for a while it'll bump up your LTFT then set your STFT to 0% and go from there. Got it?
Yeah, that went directly over your head what he is referencing a you bump an old thread for your first post... over 10 years from the OP....Ian the idea of a forum to ask questions? Perhaps after googling some of us still don’t understand so we are asking for clarification