Found a similar mess inside my engine bay, turned out to be the oil pressure valve thingy, £4 replacement from a motor spares.

That narrows it down a bit, the old faulty oil pressure valve thingy flange plug lead.![]()
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Ahh cheers lolYour engine code is Z18XER 140ps 1.8vvt 16v
The Z18XE is the older 1.8 16v without vvt and is only 123ps
The cam covers are different so do not get a Z18XE rocker gasket![]()
lol