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If I sit in my car and let it idle for a while at operating temperature, the RPMs drop to about 600 or so, and the car starts vibrating a lot. Is this normal, or am I idling too low?

If I am idling too low, is this something I can fix myself? Is there some way to adjust the cable connected to the throttle (is that even what I would do?)?

Well, the car should not be shaking at 600 rpms. My car idles around 600 once it's warmed up, of course it's a V6... Thinking back I think my Accord had a similar idle problem that somehow resolved itself. I'm not sure what regulates the idle speed besides the throttle cable (which you should be able to easily adjust from under the hood). Call in the mecanicos

Idling at 600 isn't too low. The Camaro used to idle at 800, and the Taurus idles at about 700. Recall that with the colder weather, that idle should speed up a bit, so just monitor it and make sure not to stall.

Warner wrote:If I sit in my car and let it idle for a while at operating temperature, the RPMs drop to about 600 or so, and the car starts vibrating a lot. Is this normal, or am I idling too low?

If I am idling too low, is this something I can fix myself? Is there some way to adjust the cable connected to the throttle (is that even what I would do?)?

What car is it? For most of my cars, fuel maps are learned, so disconnecting the battery for a few minutes will force the ECU to start from scratch and relearn everything. That includes idle speed, fuel/air ratios, shifting patterns (for an auto), and the radio and clock. Plus more.

I just changed the battery on the Taurus and had to relearn the shift points and idle. It learns pretty quickly, but while it was learning, it shifted a bit harshly and idled a little high. After about an hour of my slow-start driving, it had adjusted and was running nicely. Computers in cars do a lot more than we realize.

LS1Leader wrote:What car is it?

1994 Geo Prizm

1.6l, if that helps.

I don't know the details for the Geo Prizm's idle tuning, but diconnecting the battery (if you're willing to lose radio stations and such) is a good start. However, I don't think it's something you should be overly converned about, unless the engine really lugs.

Adjusting the throttle cable could achieve what you want, but I don't know if that's the proper way to adjust it. The car is fairly new, at least from the 90's, so the idle should be adjustable by some other way.

my bmw idles at 600 or 700 same as the honda (the bmw stars idling there and stays) while a cold start for the honda will be at 2100 rpms and then slowly drop..

ya i realize now that my car does wiggle, giggle around a litlte when idling but i have always seen it as normal

my STi idles at 1,500 when its first started up, but after driving for about 5 minutes it is idling at around 500-600. It's not a big deal to me but it does make starting a little less forgiving.. but I have become super comfortable in this car so its no big deal..

700 or so for mine..... I am not sure what the norm is though...