Throttle blip...why is RPM slow to drop?

[KAZ MotorSports]

I am tuning a clients car that I put some goodies on. It is a 2000 Camaro SS.

Goodies:
Cam 230/236 112 LS and .597 Lift int/ext
Kooks Long tube and Y (no cats)
Corsa Exhaust
80MM BBK TB
1.85 rockers

It idles perfect (thanks guys for all the how-to posts) and I am getting ready to tune VE and power. I figured while I ate lunch I would ask why it takes so long for the RPM to drop after a throttle blip. It isn't like it takes 10 seconds or more to drop to desired idle...but it does not instantly drop to desired idle to give that nice snap drop in RPM when in P/Neutral.

IAC steps shows 24-28 steps while sitting at my desired 875 RPM (P/N A/C off). When I blip the throttle it goes instantly to about 75-ish steps (1800-2000RPM), then the steps immediately drop to 12 or 14 until the RPM falls back off to about 900RPM. The steps chase up to the 20-25 steps to match the desired idle RPM as it falls back to 875 and in the 20's steps.

Is there anyway to get the "throttle response" a bit quicker reacting for that nice snap in RPM decelaration?

Thanks all!
-Kenny

[SSpdDmon]

1) Log throttle follower to see how fast it decays out. If that's the culprit, you need to play with the P/N decay rates (assuming this is an automatic, right?).

2) If it's not, then I'd close the throttle body set screw so warm idle is between 50~70 IAC counts/steps (actually, I'd do this regardless). Then, play with the idle learning tables so that it comes back down faster:

Spark>Idle>Overspeed Error: tell it to take more timing out like the stock file originally did.

Idle>Learning>Direct Airflow: increase the RPM High P/N column for the 300+RPM rows.

Idle>Learning>Parameters: Reduce Direct Airflow timer (maybe 0.5~0.8 seconds).

[KAZ MotorSports]

Yes it is an Auto car.

I was assuming throttle follower was only for in motion. I will look for it now.

Thank you sir!
-Kenny

[SSpdDmon]

No problem. Throttle follower is TP% & RPM based. Only the decay rates reference MPH IIRC.