Power And Idle Issue When Warm

[sleeper7]

Ok, well i've solved my problem. The cold idle control valve (not sure if that is the correct terminology, but that is what it does) is stuck open, which is why the car runs fine when it is cold (albeit idling quite high), but then as it gets warm the engine is getting too much air and it starts driving like crap. So it is pretty much a vacuum leak.

Steve, in case this solves your problem as well I'll try to go into a bit more detail so you can check it out. Just to clarify, the cold idle control valve is not the ACC idle control valve, but it is near it. You will see on the ACC valve that it has the vacuum hose coming off it yeh? That vacuum hose joins onto two other hoses with a T-Piece. The bottom hose is the one you want, follow it down and it leads to the cold idle control valve which is located near the throttle body. Doesn't look like much, it is just a sort of metal plate where the hose joins onto. This valve has a metal disc that opens when it is cold, and is meant to close when it is warm, but for some reason on my mates car it is stuck open and won't shut.

We have blocked off the bottom connector of the T-piece and the hose leading to the idle control valve (really need to block it off well because it easily becomes unstuck when you hit boost), and this has solved the problems, although it will now be a bit rough when it is cold. Otherwise it drives perfect again.

Thanks for the post mate, but there is no chance of getting this off in an r33 without taking the plenum chamber off from what i can see. Iv'e tried for two days now with no hope. I actually let the car warm up until it started to idle rough then clamped the hose, this didn't do anything at all, so i'm stumped. I'll just take it to an auto elect when I get a chance. Thanks for your help though.

Cheers Steve.