The ARV is part of the turbocharger. Find the small vacuum line to the turbo (not the big rubber wastegate hose), disconnect it, and plug it. I think even the 1986 SDL had this (but I'm not positive.)

BTW, about the idle speed thing - every once in a blue moon, my car will also do this - hangs around 1000rpm, but if you tap the throttle, it drops to normal. I gave up trying to fix it. I've heard of others doing this as well. As long as it's not happening all the time, I'd ignore it. I'm failry sure it's an internal mechanical problem, not electrical. The EDS can only raise the idle in the 550-750rpm range, not enough to cause 1000+rpm problems.