Idle wont stay at set value
It's a '00 WS6 with the MS4 cam and longtubes-cats-exhaust. So the tune isn't too radical. But am I possible running in SD? I live in Nevada and it's pretty cold here. The car was originally tuned last summer when it was 120 degrees, and the last couple of times I've driven it the temps were more like 40-50
Thanks
Generally, the idle tables are set to idle at a higher RPM with the RPM's decreasing to some stable point once the ECT has reached a normal operating value. e.g. a stock Avalanche is set to idle at 750 with ECT = 68* (F) regardless of being in Park or Gear, AC on or off. As the ECT increases towards normal operating temps, the desired idle is lowered to 550.
Does that car continue to idle high after warm up? Stick or Auto? If it were something physical (like a vacuum leak), I would not expect the idle to stay at 800 one time and then switch to 1000 the next.
Lots of things can affect idle: Did you tune the VE? You might have too much timing, and you definitely need to verify your base airflow as well. If you have modified the Cracker and/or Follower tables, you may be chasing your own tail without ensuring the base flow is correct first.

