1986 Volkswagen Van 1986 Vanagon high idle

Hello,
1986 camper van. Had the CO adjusted in Colorado (about 7000 ft) and as we've dropped in elevation the idle has risen. We're now in Fairbanks, AK (about 400 ft) and the idle is about 2600. Because of the high isle we've lost our clutch and are waiting for it to be fixed. The shop has no idea why it's high and we can't find a reputable van mechanic in the area. I tried to adjust the idle screw and found it bottomed out, cleaned the stabilization valve which changed nothing. Any ideas?

Thanks