kgoertz

Thanks Ahsai.
I checked it out this morning with the ODB scanner. Both the coolant and outside air temperature sensors were reporting reasonable temperatures (ie 60F) even when running.
But I then realized that the AC would also trigger the front fans and sure enough the fans stopped after disabling the AC on the climate control.

So my new theory is that the DME is starting the AC compressor and the front fans when cold (maybe to prevent windows from fogging or something) which is causing both a drop in voltage and an increase in load due to the A/C compressor. Somehow the increase in load must have triggered the drop in RPM before I recalibrated the e-gas.

I'm still a little (pleasantly) surprised that the e-gas calibration resolved it. But assuming the theory is correct I think this is solved.

Ahsai

Understood now. You left out the detail that the ac was on before you start the car

kgoertz

Actually I didn't realize it was on. I just leave it in auto all the time. Disabling the AC on the climate control turns it 'off' auto and I think that disables the automatic adjustment of the fan. My guess is that enabling the A/C to dry out the air on a code start is probably a feature :-)