R33 Rb25det Idle Problem, Can Someone Help?

[nut]

http://www.youtube.com/watch?v=0RuGajWd_ys

Hi guys,

It's a R33 GTS25T. When it is cold, it idles fine, after 4mins warm up, problem appears(in the video). Sometimes, after 10mins driving, it just getting worse. When i stop at traffic light, rev could drop to 400-500 and start fluctuation between 400-700rpm, and the car shudders. I have to keep the rev at around 1000rpm to prevent stalling, but I can still feel it shudders a bit. The headlights go dim when rev drops, voltage also drops a bit. I checked the alternator belt, it seems still tight. Sometimes the voltage is not stable, changes between 13.9-14.2.

It drives fine, i mean, if i keep the rev higher than 2000, hard to feel any problem. It seems only happens when car is standstill after warmed up.

AFM is good, AAC valve has been cleaned. spark plugs are new.

maybe the O2 sensor? But O2 sensor problem seems worse than this one...

maybe the alternator itself?

[gotRICE?]

The BOV is recirculated right? Thats what the black pipe passing the radiator is?

It could be as simple as an air leak in that dodgy looking manifold

[TurboDoseBro]

That's funny cause i've got that problem only when it's cold. So opposite yours.

[blind_elk]

Have you checked the cold start air valve (on the underside of the inlet plenum)?