I would Google Search previous posts but I Google Searched the Google Search feature and it's apparently in the Webmaster's suitcase,...somewhere.
Start, warm up. Before up to temp the idle begins to surge, rev to about 2 grand and kill, drop back to maybe 800 rpm.
Repeat, as long as it takes to get to normal operating temperature.
That's the aux air valve malfunctioning, yes ? If so, is it about screwing around with the little hex nut, (which way ?), or pulling for the full freezer test, clean, lube,...
Or just hold the pedal at two grand and ignore it.