Kia Optima p2096, no LTFT

Just bought a 2008 Kia Optima 2.4L 183k miles. It sat under a tree for a year or so. Mouse nest in cabin air filter. CEL on with p2096. Burned the half a tank of old gas out of it, filled up with fresh gas. P2096 is persistent. Engine pings moderately.
Using the few kia-compatible tools I have to log data. Confused. Scan tool indicates closed loop fueling. LTFT perpetually stuck at 0.0%. STFT oscillates +/- 5%. o2s1 switching looks healthy(to me) and indicates proper a/f mixture. o2s2 is steady around .8 with engine warmed up.

Forgive this ugly log. I created a lean condition and this is how the system responded. Top graph is red ltft/green stft, bottom log is green o2s1/red o2s2.
The oil doesn't smell like gas.
I've ordered new spark plugs, engine air filter, and fuel filter as standard tuneup items for an old car that's been sitting. Not sure how to proceed with this issue.
Recommendations for a competent, cheap scan tool to use on this car?

I'd suggest carefully checking the exhaust for any exhaust leaks between the upstream and downstream O2 sensors. Cracks, pinholes, anything. Listen with a mechanics stethoscope. Soapy water can be helpful, but only when the exhaust is cold. Hot exhaust will just boil the water off. :lol:

Thank you. An exhaust leak didn't occur to me before but it makes sense. I haven't smelled or heard any evidence of one but I'll look it over closely.

I've kept driving it and the pinging has mostly subsided and the CEL turned off for now. I inspected for exhaust leaks and couldn't really find anything. o2s12 is still reading rich but apparently not enough to set the code. If the code sets again I'll check and advise.
Replaced the air filter and cleaned the maf and it seems to be idling a bit smoother.

Cleaning the MAF was a good idea Kia are really sensistive to MAF calibration and dont tolerate aftermarket MAFs well.

MAF seems oem to me but I didn't look very close. After replacing the air filter I took it for a ride and the CEL popped on and I was wondering why it was idling like shit. Then I realized I didn't have the maf connector fully seated. That caused maf, IAT codes as well as p2096.
I still have no long term fuel trim though, even after driving the car for a bit with no CEL. Does it need to finish a drive cycle or something? Would it be smart or worthwhile to reset the computer via the alligator clipped battery cables technique?

I noticed the lean condition was causing the car to go into OL-drive with virtually any load on the engine.
I replaced the fuel filter and spark plugs and its running pretty good now. It's no longer going lean and the fuel control is working better. It's staying in closed loop except when it shouldn't. I haven't noticed any pinging and it pulls better.
o2s2 is still reading rich. No p2096 but also no LTFT still.

It's still running and has been mostly CEL free since my last post. No p2096, but I had a p0420 set once in the past 1000 miles. Cleared and it hasn't come back.
I have some LTFT action but its strange. Responds intermittently and changes in increments of .8. Stays around 0% +/- 5%.
Pinging is mostly gone besides occasionally at WOT it will ping up a storm. Not sure what's up with that.