idle speed query

[peeeot]

I've gathered from reading in the forum that 900 rpm is a common idle spped for the 3.4 V6 (manual). I've also gathered that several people have idle speeds closer to 700 rpm. I only expect idle rpms in the 900 range from 4-cylinders; does anyone know why the 3.4s are set up to idle so fast? Is there a way to decrease the idle speed, and if so, is it advisable? Seems like a waste of gas....

[hockeyman]

Set your idle for 700 rpm's and turn on the air conditioner or defrosters. Be ready to restart your car.

[slow6]

look into pulleys?
maybe electric water pump

my car has probs with idling so low, yes i need tuning bad

[98Camaro3.8]

FWIW, many people (ie, 99%) may be judging the idle speed by the tachometer, which is not extremely accurate for that purpose.

[peeeot]

I am judging based on the tach; what reason do I have not to trust it?

I don't know how to set idle speed on a computer controlled car, but I do know that for the current idle settings, the computer adjusts throttle (via IAC) and fuel settings to maintain the set idle speed under loaded idle conditions, i.e. with the A/C on and/or fan blowing hard or lights on or what have you. My car idles at the same speed regardless of what I have on or not, and that's around 900 rpm. I am not aware of any reason why the car could not carry out these same functions at a lower rpm setting, like the family minivan does or my brother's '66 Mustang (with a 200 ci I6 and factory a/c). Both of these vehicles have no problems dealing with any idle load and an initial idle speed of approx. 700-750 rpm. Incidentally, they're all within a couple ci's of one another as well.

What gives?