Oil in engine wiring connectors
VAUXHALL Corsa Mk III (D) Hatchback (S07)

Hi all im writing in this forum to ask for help. The issue with my corsa model d from 2007 1.0litre is that about 5 months ago my 02 bank 1 sensor broke and since then i replaced it to the  cheap one (wasn’t worth it). Then the new 02 sensor broke again and found oil in the harnis connector. Ive went to the mechanic as the engine ran rough (I reset the ECU with and obd2 reader the issue went away for 2 days and then came back). The mechanic replaced the ignition coil pack, air flow sensor, spark plugs and the old 02 sensor for a denso 02 lamba sensor. All that didnt help and oil was found in all the wiring connection to these new parts after 5 days of being fitted – the rough engine feeling came back. A newly discovered issue is the oil pressure swith has started to leak abit of oil from its seal but I havent got a clue if that will cause  the issue of oil in my wiring harnis.

Any advise  will be much appreciated. Any ideas to what I should look at to replace for my car to work correctly again.