idle smoothness

[rover3l]

When a Q is idling in Park what is the acceptable tolerance on idle speed variation. Mine is 550 rpm plus minus 30

[Q45tech]

Specified idle speed in park is 750 rpm +-50! Warm no AC no lights.

[elwesso]

Dennis... My idle is various.... When cold, its at 1250, when warmed slightly at 750, and when fully warmed its about 900..... Sticky IAC???

[rover3l]

not sure how mine got to 550 rpm hot, no AC, no lights. Is there any reason I should adjust it as it runs ok without stalling.

[Q45denver]

Dennis... My idle is various.... When cold, its at 1250, when warmed slightly at 750, and when fully warmed its about 900..... Sticky IAC???

Mine is similiar. It is a real problem in the winter as the power of the engine at such a high idle tends to overpower the brakes and reduces the stopping distances considerably. This is particularilly true if snow tires have not been installed. How would I go about reducing the idle speed?

[Q45tech]

Duh! You are supposed to warm the car up [before moving it] the 1500>1250>1000>750 follows the coolant temperature rise.

If you don't have a block/rad/oil heater or a heated garage.

The FSM is CLEAR AS A BELL that idle speed must be set a correct operating temperature 176F.

All 90+ cars work in similiar ways.Crank and go [in winter] does serious stress to an engine without the 5-10 minutes of temperature normilization .

[Q451990]

Q45Denver and Wes,

Does the idle stabilize after warm-up at 750, or 900??

Heath

[elwesso]

The idle stabilizes around 900..... When you run it for 10+ mins, thats where it goes.....

I decided to up the idle a little because it woudl sit around 500 at stoplights and the whole thing would shake.....

[Q451990]

I'd say that's a little too much! Should stabilize at about 750... any more than that to smooth things out is covering up another problem (most likely plenum dirt, dirty TB, and dirty injectors).

Heath

[Q45tech]

Every rpm more than necessary, burns gasoline........900 vs 750 rpm burns 20% more than you should!

[elwesso]

Well I just adjusted it up higher so it wouldnt vibrate.....

Im gonna be doing the plenum job in a few weeks!!! So Ill adjust it correctly then!!!

[Jesda]

Everyone ought to invest in remote start. Make it part of your morning routine, or start up the Q when youre in line checking out at the store. Start estimating 10 minutes from when youre going to hop in the car. Plus, its nice to get in a proper climate cabin in harsh winters or brutal summers.

[elwesso]

I just figured out something.... When I was doing my weekly inspection of the underhood area, the car was idling for about 5 mins with the hood open.... When I got out of the car (before I opened the hood) it was at about 900 rpm, and then when I got back in (hood open for 5 mins idling) it was back down 750....