I feel like I've already used up all my questions on this site but I AM IN NEED of someone's two cents about my Z's current state. As far as I'm aware, on 9/15/22, my Z has stored a PENDING code P0174 for Bank 2 running too lean. So far it hasn't illuminated the CEL, yet. I went for a drive around 3AM to see what was going on with my Banks and from what I could tell on the live graph, Bank 1 seems to be operating normally (Both A/F Alpha b1 & NB Sns1 b1), But Bank 2 seems to be confused(?). A/F Alpha b2 only sticks to EXACTLY 100 when the gas pedal isn't being used, but then gradually INCREASES to 125 and sticks there when even the slightest amount of pressure is pressed down on the gas pedal. When set to cruise, it goes from 100 to 125, stays at 125 for 7-9 seconds, and then resets back to 100, only to climb to 125 again after a second or two. As far as NB Sns2 b2 goes, it likes to stay high up around 0.75 - 0.95 but does return to lower numbers when neutral rolling or slowing down, only with a little delay.

This is practically the first time I got to drive my Z in 10 months and during that time it has underwent modifications and repairs. To name a few:

• Invidia HFC
• Complete Invidia Gemini Cat-back Exhaust System
• 2 new o2 sensors on the exhaust manifolds

I was able to get the two o2 sensors off of the old catalytic converters and use those on the high flows. The passenger side o2 sensor went in all the way but the driver side sits about a little over 1/4 of the way out from flush due to bad threads from the removal process. The two new o2 sensors on the exhaust manifolds were installed by a shop. The car does not have a tune since the majority of parts (performance wise) are stock (People on this forum from older posts say installing high flows don't necessarily warrant a tune?)

the green and yellow represent bank 2

you can see the pattern halfway from 100 to 125 with cruise control

I'm just really puzzled at what could possibly be causing this to happen. The NB bank 2 could possibly be because of the o2 sensor sitting a little far out, but other than that, I don't know what exactly I'm facing here. The car drives "normally", no popping or banging noise coming from the car, only rev to 4K max, and doesn't overheat.

 

UPDATE:

I did a Clear Self Learn on the ECM and it seemed to somewhat "fix" the problem, but not entirely. A/F Alpha b2 now just sits constantly at 100. The car shot a code P0152, erased it to see if it would come back and it didn't. I checked the Fuel System too to see how that was handling. Fuel system 1 is closed loop while Fuel system 2 remains open loop? (Probably a good time to mention too that the passenger side fuel pump was also replaced). I'm by no means an expert on this, but I would like to know what's going on and why it's acting this way.