YACT: Idling RPMs are off

[Mookow]

This is a 1997 Civic LX, manual transmission, with 133K miles. Recently, when I start the car, it idles high (roughly 1700-1800 RPM), then settles over a period of 5 minutes or so to it's normal idle of about 850 RPM. What are the potential causes of this?

 

[NutBucket]

Uh, most any car does this. It idles high when cold to warm up faster. I'm shocked it didn't do this before!

 

[jtvang125]

Originally posted by: Mookow
This is a 1997 Civic LX, manual transmission, with 133K miles. Recently, when I start the car, it idles high (roughly 1700-1800 RPM), then settles over a period of 5 minutes or so to it's normal idle of about 850 RPM. What are the potential causes of this?

Um, because it's colder now therefore the car is revving a little higher to get up to temperature quicker??

 

[Heisenberg]

They are supposed to idle faster when cold, but that sounds too high to me (fast idle for my cars is around 1000-1200 RPM). It's probably the idle air control motor.

 

[Mookow]

Originally posted by: NutBucket
Uh, most any car does this. It idles high when cold to warm up faster. I'm shocked it didn't do this before!

Before it would do that at maybe 1100 RPMs. And that is in the dead of winter in Cleveland. Right now it is nowhere near that cold, it starts idling at 1800 RPM.

 

[NutBucket]

Ah. I see. Yeah, there's a few idle control motors and such. If I was you I wouldn't bother fixing it unless it gets a lot worse. Is it a rough idle at all?