I'm curious. :roll:
Why do our cars (or many cars that I know) idle at around 600 rpm ? Can it be lower or higher and why?

Can anyone explain ?

my car idles' up and down sometimes...is that something with the ground/electrical?

Mine was around 800 until I did a ground wire mod now it is lower.

god works in mysterious ways

you can have the car idle at redline.

it idles at a rpm that smooth. any lower it would feel like it will stall

it has to deal with inertia....

Mine was around 800 until I did a ground wire mod now it is lower.

how much lower did your rpm's go down? or where does it idle at now?

you can have the car idle at redline.

it idles at a rpm that smooth. any lower it would feel like it will stall

it has to deal with inertia....

would that mean each car would be slighty different in idle?

if i dont get/have a ground kit would that also be hurtful to the car then? or would it be just something that would be hp robbing?

Mine was around 800 until I did a ground wire mod now it is lower.

how much lower did your rpm's go down? or where does it idle at now?

About 600, I was worried that I screwed something up so I reset my ECU but that made no difference.

there is a set screw on the throtle body that will adjust the closed position of the butterfly.

the ecu will detect the air flow and have the injectors mix in the proper amount of fuel.

keep the butterfly open more the idle will go up.
close it and the idle will go down. if you turn it down too far the car could stall if the A/C turns on....

IC. Let's recap, I guess, at 600 rpm is the minimum level that the car doesn't stall, even if the AC is on. Thanks for posting :)
My car's idle very steady around 600-700 even when I change from neutral to drive. Ground wires make that happen :) .

im happy with the idle at 600 rpm compared to my explorer which idled at 1500 rpm its alot less noisy and smoother

High idle= 100-1200 RPM

Low Idle= 500-600 RPM

my car idles' up and down sometimes...is that something with the ground/electrical?

Think about the last time you noticed it ideling up and down. You might have had the defroster on and the A/C compressor was automatically engaged. At full warm idle, move the HVAC control from "anything" to "defrost" and you can see the tach jump up slightly as the computer tells the motor to compensate for the compressor. Same thing can be seen as you hit the A/C button manually. On a sidenote winter MPG usually goes down some inpart to a "richer" cold start warmup but also because of the use of the compressor in "defrost' mode.

well idle is all how your cam is if u have a big lumpy cam like i have in my v-8 car it does not want to idle low but our cars have like what i like to call truck cams they are not lump they make it have a good idle and good power band and if u notice scions dont rev all that fast too that has to do with the cam but with my v-8 car it revs quick its all has to do with the cam but yeah your car is fine if it idles at 600 my does to when it warms up so all in all your fine

there is a TSB on the stumbling idle, mine does it too havent had tome for the TSB to be performed.

What's a TSB?

Technical Service Buliton, its somthing released by Toyota that there is a problem and it has the fix.. if you take your car to the dealership and tell them what its doing, firt thing they do is look up the TSB to see if its listed..