Fuel Trim maxes out on Park or Neutral at idle

1999 Acura Integra with 150k Auto LS and well maintained.

LTFT maxes out at idle on Park or Neutral throwing P0171.
When driving it comes down clearing CEL and seems to settle around 12.

Lot of the parts were changed to fix SMOG issue and a misfire. Emissions are perfect now.
Has a reman injectors (had misfire), new Sparks, Fuel filter.
Fuel pressure with and without regulator is good. Compression is good. Passed leak down test.

While back it threw P0505 and cleaned the IAC valve and issue was resolved. Idle speed is within spec and does not fluctuate.

On Park or Netural, LTFT increases at idle and 1500 rpm but comes down on 2500rpm.
At idle, if you shift it to D4, then LTFT comes down too. Just Park and Neutral are issues.
Also possible at Idle on Park, if you turn on the AC, then it no longer maxes out.

You can see in the first photo below that LTFT ramps up on Park - then I moved it to D4 and it started coming down.


Also, if I introduce a vacuum leak by loosening the IAC valve botls, LTFT does not increase at idle. Pls see in the 2nd photo - there is spikes in rpm.


Despite this, car later passed SMOG - initially failed on NOx twice - below are the final NOx:
15mph 81 → 357-> 578 (from highest 578 to 81)
25mph 44 → 1079-> 639 (from highest 1079 to 44)

What seems to be causing it?

Updated:
New front O2 sensor

While in park, raise your rpm to 2500 and hold it stead while monitoring STFT and LTFT. If STFT COMPENSATES TO BRING IT BACK TO 0 then look for a vacuum leak. If not, then verify oxygen sensors by driving rich and lean both electrically and by simulating rich and lean conditions. If good there test for for exhaust leaks.

I updated my post - it has a new front O2 sensor.

I can try at 2500 rpm as u stated - but FTs have been positive even before this issue. See below the #s. They are never zero. Now I have many new parts so it could potentially become zero - I was anticipating after the shop repaired it - instead the car developed this issue. Shop did not have a smoke m/c but could not sense an exhaust leak with his fingers
Fuel Trim:
Originally before the issue:
1500 rpm 2500 rpm
LTFT 6.2 6.2
STFT 6.2 8.6

After I disconnected the battery and let all the Capacitors discharge at idle:
LTFT – 4.6 4.6
STFT – 7.8 – 12.5

Should the LTFT become zero as per your test?

While in park, raise your rpm to 2500 and hold it stead while monitoring STFT and LTFT. If STFT COMPENSATES TO BRING IT BACK TO 0 then look for a vacuum leak. If not, then verify oxygen sensors by driving rich and lean both electrically and by simulating rich and lean conditions. If good there test for for exhaust leaks.

New doesn’t mean good. The test I mentioned will absolutely prove whether or not you have a vacuum leak or not.

I also want to see oxygen sensor and TPS data with a snap throttle and a road test WOT with TPS. The oxygen sensors should both go rich.

You can always use a shopvac on the blower end and place it in the exhaust and spray the exhaust around the cat when it’s completely cool and look for bubbles.

One thing changed lately - LTFT had gone down from 11.7 to 9.375. So at idle & Park at 2500rpm, it still was climbing up to 11,7.
Secondly these were done when the coolant is at 172 and Closed Loop.

I did the WOT first - repeated it again. So WOT happened as below and photo below too:
35 - 40 1st WOT
75 - 80 2nd WOT



Then at 95, I did Park gear and 2500rpm:



Then I started driving and LTFT came down:


Should I perform the snap throttle at Park gear and engine is warm?