Cruise Control

https://www.cargurus.com/Cars/Discussion-t16263_ds498936

check for any recalls..

Cruise control often uses engine vacuum tapped off the intake manifold of the engine. Look for loose or missing hoses. You might hear a hissing sound from the engine while idling, caused by that missing hose. Older hoses dry out and work loose or are blown off if the engine ever backfires. I hope this helps.