Help - Ecotec RPM lingers high.

[Rat Chevelle]

Hello,
We are using a 2.2 Ecotec out of a 2007 Malibu on an off road buggy, the issue is that the RPM does not climb down fast enough when you let off the pedal, they linger for a second or two at 3Kand then slowly come down.
Now to make this more frustrating the moment I try to tweak the tables the pedal dies and it throws a P0606 code IIRC.
I usually deal more with V8's but this little thing moves very nice on dirt and it is exciting, I would like to solve this issue to make it more enjoyable.
I have atached the file, any help will be appreciated.
Thanks

[projectlnf]

are you still running the automatic trans off the malibu?

[Rat Chevelle]

No, I am not.
I set the transmission to manual, and I do not even have a VSS, thats why I tried to switch on calibration from VSS to RPM, but the ETC kept failing like that.
Granted it returned to idle a bit faster, as the engine hovered around 2K for a couple seconds and then down to 800 rpm.
But I had to return it to the known VSS calibration

[projectlnf]

No, I am not.
I set the transmission to manual, and I do not even have a VSS, thats why I tried to switch on calibration from VSS to RPM, but the ETC kept failing like that.
Granted it returned to idle a bit faster, as the engine hovered around 2K for a couple seconds and then down to 800 rpm.
But I had to return it to the known VSS calibration

this kind of sounds like what we see here at my dealer.. in the scanner i think there is a idle relearn procedure.. try that to see if it helps.. and try to get a log of it doing it. are you running a MAF sensor or are you speed density?