O2 sensor graphs. Is my sensor bad?

[ahsanonline]

It's a 660cc kei car.
Drivability isn't that great.
Feel jerks on partial acceleration and rhythmic surging.
No DTCs.
Fuel economy isn't great.
LTFT remains around -5% (minus five).

I'm attaching these o2 sensor graphs; driving conditions that can be seen from the throttle and engine rpm graphs. Engine is fully warmed up.

Is the O2 sensor lazy? Is it at fault?

[Xulfiqar]

You have a leaky injector or valve.

[ahsanonline]

Thx bro. Long time.

How do I diagnose which one it is? I do smell raw fuel from the exhaust in the morning startup.

[ahsanonline]

So I used the liquid moly proline throttle and intake cleaner. Idles much better now. Going to replace spark plugs; the current ones' ground electrode is pitted (worn).