idle it too high when coasting...

[mbrac]

So I'm driving a 2007 Focus - 2.0 L - and it seems like when I'm coasting - the idle stays around 1500 - and does not go down to 750 until I come to a complete stop. With this condition - it almost defeats the purpose of shifting into neutral when coasting up to a stop. Anyone know what might be causing this? I don't think it's the TPS as the pedal does not get touched from the time I shift into neutral to the time the vehicle comes to a complete stop. Any advice would be appreciated - Thanks!

[Daox]

My 05 Aveo did the same thing along with my 03 Matrix. I think its a "feature" to make the car more drivable for the normal putz.

[SentraSE-R]

Clean your Idle Air Control Valve? My '06 Scion xB MT & Hyundai Elantra AT drop quickly to 700-750 rpm in neutral.

[drmiller100]

do you have a check engine light on?

a vacuum leak will cause high idle, but usually you will get a check engine light with it.

[mbrac]

Thanks everyone for your input - I think I'm going to try cleaning the Idle Air Control Valve - since it's only affecting it when coasting - if that dosen't do it - I'll just replace it- cost from Autozone is $54 - no error codes - just noticed it since I became an ecomodder...

[drmiller100]

is this a 5 speed car?
If so, then I bet it is "desired" by the ECU.

The ECU cannot tell what gear you are in on a 5 speed. And there are less pumping lossses with a higher throttle opening on deceleration with the car in gear. So I bet the ECU is opening the IAC valve to let the car coast "better", and you are fooling it by shifting into neutral.

[tru]

I was suggested by a co-worker to detach the IAC and adjust the throttle position manually so the car idles where you want, not what the general public wants. I just dont know where the dang thing is on my engine lol.

Please let us know if changing it helps, however, i think yours is working as designed.

[drmiller100]

The IAC will almost always be in the throttle body, which is at the top or "front" of the intake. It will have a plug with a 5 to 10 wires going to it.

If you unplug it on a 1996 or newer car, the ECU will throw a code. My GUESS GUESS GUESS is this will not throw the engine into limp home mode, but it will cause idling issues.

[mbrac]

That makes perfect sense - about the coasting - so I guess I either have to live with it or find a way around it - I try to do allot of coasting to stop signs and redlights - etc - and it the idle is 1500 that whole time - it's just a waste of gas - Oh, and yes, it is a 5 speed. Thanks again for your knowledge on this subject - it helps me make more informed decisions on what to do next.

[JRMichler]

My Canyon does the same thing, and has done it since it was new. The dealer said: "No trouble code means no problem". So I put in a kill switch and eliminated almost all idling.