Help, Mot failure, High emmisions

[parrot]

I can't see what you are describing on your picture, although the vacuum pipe from the fuel pressure regulator to the plenum looks a bit ordinary, though may be the angle. There is a vaccum take off with three outlets from the plenum as described above. One goes to the fuel pressure reg, one to the MAP sensor, and on JDM cars, the other is usually blanked off. Your third port looks to have a christmas tree hanging off it. I would get rid of that and blank it off properly as it is probably leaking. Any air leak would presumably lead to the ECU trying to richen up the mixture.

UKDM cars have a variable resistor (VAF) located by on the strut tower near the coil/ignitor to adjust idle CO2. If yours is a JDM import it will have an oxygen sensor situated in the exhaust maniold instead. If it has aftermarket headers it is quite possible the oxygen sensor was not reinstalled thus there is no feedback to the ECU.

Lastly, I would thoroughly check for an exhaust leak.