Hey there, so I recently bought a 2016 Skoda Octavia III g-tec

A couple of days later the car started idling very rough and the check engine light popped up

It seems very inconsistent, but is worse when idling after starting the car warm

Codes that pop up are:

Misfire cyl 3

O2 sensor faulty

Long story short I've changed both o2 sensors, injectors, coil packs, spark plugs and changed all oils but to no avail

Any tips for the next step?

Edit, seems like battery voltage is 12.2v while idling, going to test it again in the morning. Would that have any effect on the rough idle though?

12.2v is quite low for idle, will drop even more when engine is at higher revs. Can't say for sure, but low battery voltage causes all kinds of weird issues so that would be my next troubleshooting/maintenance step.

I'd remove the battery and hook it up to a charger overnight to see if it helps.

Edited 13 June, 202513 Jun by Ripmax12345