High Idle Problem

[PhilGTR]

Hey guys,

I have a bit of an idle problem that has been hanging around for a while since i got my engine rebuilt about 5000ks ago and its still bugging me. Before the rebuild it was fine. Here are the symptoms.

When I had the stock ECU when i first start it up in the morning it would idle at like 1800 rpm when cold. When it is warm it would idle usually between 1100-1600rpm. Sometimes up to 2000rpm, but very rarely. If i have the fan or a/c on it would idle at like 2000rpm sometimes. Now my mechanic has checked everything like the aac valve and idle screws but could find nothing wrong with it. So he suggested maybe an ECU problem

Now I have got a power FC and the problem is still there but slightly different. When i first start up the car whether warm or cold it goes to 2000rpm, and probably sits there for about 10-20secs and then drops down to like 1400rpm. And once i start driving for a while when i come to a stop, it would only go down to 1800rpm, then after like 5 secs or so, it would drop down to like 1400 to 1100 rpm and stay there. But if i had the a/c on or fans on it would keep idling at 2000rpm. This is really annoying! And i dont know much about the pfc as my tuner installed it and set it up for me.

Unique said the idle problem could be something to do with the rebuild. Im not sure what the part was called but he said its in the intake manifold and that it has been cleaned or machined too much and thats why its idling so high. What is going on with my car?? Does anyone have any advice for me?? I really wanna get this fixed up.

Thanks everyone!

[Medium Dave]

I have a similar problem that goes away for a few days everytime I change something, has been very frustrating, the last thing I did was to re-gas the air con, as I was told it could be to do with the dual pressure switch, it worked for a few days, now I have hunting again... but do a bit of a search for hunting, you might find a few ideas

[SLIPPERY]

possibly not a good seal between gaskets, throttles and head when the plenum was put back on? =>uneven/ warped surfaces that suck in too much air?

[PhilGTR]

woo hoo finally its fixed after pulling off the plenum and checking the throttle plate and cleaning the aac valve its finally like a normal skyline!

Edited September 7, 2006 by PhilGTR