Passed NCT today.
Just in case anybody ever gets a similar fail:
Had failed on emissions, high idle CO 4.94%, the tester said this reading was behaving erratically.
I had used a known good lamda sensor and ect, so i knew they were not to blame.
Problem turned out to be Intake air control valve position sensor.
Used blink code method to find fault.
Code 62 present.
From fto handbook this points to the above sensor.
Replaced sensor.
Emissons passed CO 0.21%.
They are probably on here already but i have also listed various other engine error codes.
11 Oxygen Sensor
12 Air Flow Sensor
13 Intake air temperature sensor
14 Throttle position sensor
15 ISC Motor Position Sensor
21 Engine coolant temperature sensor
22 Crank angle sensor
23 Camshaft position sensor
24 Vehicle speed sensor
25 BARO Sensor (listed as 26 in one info source)
31 Detonation sensor
32 Vacuum sensor
36 Ignition Timing Adjustment Signal
39 Oxygen Sensor
41 Injector system
42 Fuel Pump
43 EGR
44 Ignition coil and power transistor unit (Cylinder 1 & 4)
52 Ignition coil and power transistor unit (Cylinder 2 & 5)
53 Ignition coil and power transistor unit (Cylinder 3 & 6)
55 Idle Air Control Valve/Servo Valve Position Sensor
61 Communications wire with A/T-ECU
62 Intake air control valve position sensor
64 Alternator FR terminal
71 Vacuum control solenoid valve (TCL)
72 Ventilation control solenoid valve (TCL)