P1117 - can't clear code

[Zzorro]

98 with 175k kms. All original. No performance mods etc.

I have a durametric so can see codes. I have done my research on here and have O2 sensors on order.

My question: has anyone ever had this issue? And did replacing O2 sensors fix it?

My symptoms:
-CEL: duh. comes on and throws a raft of codes. It's infrequent however. Codes were as follows. NOTE: I can clear the P1117. It's persistent. I can clear the other codes without issue.

P1117 -Heating power 02S behind cat c bank 1

P1319 - Misfire emissions-relevant

P1313 - Cylinder 1 misfire emissions-relevant

P1314 - Cylinder 2 misfire emissions-relevant

P1316 - Cylinder 4 misfire emissions-relevant

P1317 - Cylinder 5 misfire emissions-relevant

P0410 - Secondary air injection system Cylinder (1-3) Signal implausible

P1411- Secondary air injection system Cylinder (4-6) Signal implausible

P1128 - Oxygen sensing range 2 Cylinder (1-3)

P1130 - Oxygen sensing range 2 Cylinder (4-6)

-Performance: minor sluggishness in performance until above 3000rpm. Then is comes totally alive (almost feels like turbo lag!).

-Performance: infrequently I get a major bogging at higher revs. Feels like a sudden loss of power and like fuel is getting cut. Lift off the throttle and the car idles fine. Lasts for maybe 5 seconds. Then fixes itself. Sometimes CEL comes on. Most times not.

-smells like it's running rich at idle.

What I've replaced so far: MAF (made a big difference), all coils and all plugs, fuel pump.

What I've looked at: tried to find a vacuum leak as research leads me to believe this is the culprit for these kinds of codes. Could not find one easily. Decided to tackle O2 sensors 1st after persistent code started occurring.

I'll post back here once I've done the mods to let others know what happens when I swap the sensors.