Weird idling thing

[moosepig]

If I pull away from a slow rolling start in 1st gear, accelerate on full power for 1 or 2 seconds, then come right off the gas, the engine idling speed sometimes increases to about 1500 rpm for up to 10 seconds before dropping back down to normal of its own accord.

I notice this particularly when pulling onto busy roundabouts and then having to slow for traffic and getting no engine braking as the high idling speed is driving me along.

It's an '04 CV8 with Wortec Focus Pac.

Any ideas, anyone?

[BO55 VXR]

Now you mention it, I think mine does that on occasions... tis truly weird

[V8HSV]

I thought all cars do this, well my hsv & 2 smarts do!

[ringram]

Its the tune, though if you decide to drop it too much you can end up with too low an idle, and a possible stall.
The wortec tune is probably set up to make sure you dont stall. A tune is always a compromise. Best idea if you are keen enough is to tune it yourself. efilve or hptuners are the solution to tweak it to your satisfaction. eflive gets my vote.

[wortec1]

It happens on standard cars too if you do what you say on a hot day....

[pomona]

Throttle cracker,setting of idle screw on throttle body,throttle blade idle air hole and EFILive flashscan can cure the problem.
Had same on my GTS-R (only when modified) but rectified by mechanical/electronic tune.

[ringram]

Yep, and throttle follower too Follower decay rate probably also in this instance.
Nothing is ever perfect unless you do it to how you want. Whats good for one is not good for all. Tunes are very personal. Some like a slow and lumpy idle, other like it smooth, some like a touchy throttle, others like progressive throttle etc.
The best thing about these cars is that they are so tuneable. Anyone with a remap knows the benefits of this.

Edited by ringram on Friday 7th July 19:50

[alfienoakes]

I noticed it too, but only with the A/C on. I'll get round to tuning it out when I can be assed....

[v8d]

I have spotted this on a few occasions, seems to depend what you are doing when it comes off the throttle. I have EFI live flashscan, but Wortec tunes are locked down so theres bugger all I can do about it.... Hey Ho ! Its certainly not what I'd call a prob.