Idle
 

When i start the car when engine is cold my ilde go up as high as 1500. Isn't it should be 3K? Cold weather have something to do with it? Or something else is wrong?

I also have high idle at the first 2 minutes starting. You can just shift to the first gear 1 or 2 mins to pull down your idle. For the detail reasons, I really don't know why. :o

I really do not think that it is anything to worry about, my car does the same thing in cold weather. As far as I can tell, you do not want the car to warm up at 3000 rpm's and should start the car in gear or quickly press on the gas pedal to prevent it from doing it.

...although what is weird with my idle, my car will startup, after I press the gas it will idle smoothly at 1500 and then once my Greddy turbo timer activates, I start getting a rough idle. That normally goes away after a minute, but it sure is annoying.

Isn't it suppose to hit around 3k when first start then drop down 1.5k? I confuse!!!!!!!!

I believe that when the car is started in neutral, it is supposed to idle at ~3000 rpm for about 20 seconds in order to quickly heat up the main cat. If you blip the throttle or start the car in gear, it will idle at ~1500 rpm.

The accelerated warmup system (AWS) runs the engine at 3K on my car in warm weather, but when cold it's more like 1500 rpm. I'd put that down to the 10W-30 in the crankcase being thicker in the cold and not worry about it. It's better for any motor not to run 3K right away when it's stone cold.

In my 3rd gen I can kick it down from the AWS high idle just by tapping the gas pedal. Give it a try.

A way around the cold start is to crank the car and immediately turn it off. The second start second should put it at 750 rpms or your set idle. It is said that the cold start is not healthy for the engine because of the high rpm jolt with cold oil. Always let your car warm up a few minutes before driving.G...