Check the top of the dip stick has an o ring on it

And the oil cap seal is ok if you haven’t already

Smoke test the cam covers and breather system if you haven’t already

done all of em, i replaced the orings to be safe as well. 20% is a substantial air leak tbh. so if i had to guess its probably the TB being more open than it should be and the system is compromising by dumping more fuel so keep it idling smoothly.

so got to my throttle body. turns out the metal gasket wasnt seated properly and it was interfering with the throttle plate opening and closing.

now at this time i yoloed it since the 2nd hand throttle body hadnt turned up, I went to RR, forked out 250quid for a new one.

so I just installed the new one, i was running out of time and didn't fancy finding out if it was the plate hitting the gasket.

reset adaptations, ill let it relearn and go from there.

oh fyi the new 10% pulley, seems to of made a difference but the knock sensor also went off on bank 1, not sure if related or not. cleared it and we'll see how it goes.