Elise Idle speed problem

[eos]

I am having a problem regarding the idle speed on my series 2 Elise and would appreciate any feedback or comments which may pinpoint the problem.
Basically the idle speed is running at 1500-1600 rpm, and backing the adjustment screw right off to the point of it not doing anything has no effect.
The problem has remained even after a recent battery change and I have also left the car at idle for quite a period so the management system had a chance to re-calibrate if need be.
A mechanic has already ruled out any issues with leaking pipes and manifolds etc and assures me this isn't the problem.
He has made some wiring checks without uncovering anything but has mentioned the stepper motor could be a possible cause.
However before going any further I would welcome any feedback on possible causes, or if the Elise tends to suffer a particular problem regarding this issue.

Thanks - Your help is appreciated Eos

[wacattack]

Could be throttle position sensor...

http://wiki.seloc.org/a/Throttle_Position_Sensor

Scroll further down and you can do a manual recalibration

[Justin S]

if it fluctuates around that speed, I would look at the icav, which is on the inlet manifold and controls the idle air. Your mechanic must be awre of these as they do give problems. You can unbolt it and clean with carb cleaner and refit in 20 mins, so worth the first go at this. The other thing to do is a throttle reset if you have taken the battery off and the basics of checking the throttle is returning and not partially sticking.............

[nick_j007]

Justin S said:

if it fluctuates around that speed, I would look at the icav, which is on the inlet manifold and controls the idle air. Your mechanic must be awre of these as they do give problems. You can unbolt it and clean with carb cleaner and refit in 20 mins, so worth the first go at this. The other thing to do is a throttle reset if you have taken the battery off and the basics of checking the throttle is returning and not partially sticking.............

I've done this a couple of times in 2 years and it has helped a bit of rev hunting for sure: http://wiki.seloc.org/a/IACV