You are asking about the sensors on the back of the engine. Looking at my FSM there is only one that looks like it has vacuum lines on it and it has nothing to do with idle up. It is a BVSV, one line comes from the charcoal canister and the other goes to a purge port on the throttle body. It is part of the emission system. It must open up when the engine reaches operating temperature and sucks the fumes out of the C.C.

David Fritzsche
1990 Ex-Cab V-6,5-speed, with a few mods
04.5 CTD Dodge 2500 Ram--Tow Rig
Roseville, CA

"Serenity through Sobriety"