My cruise control has recently stopped working. It will engage, but will not maintain the speed. After its engaged it loses speed, steadys, loses more speed, steadys, ect. However, it loses the speed very quickly. Is this caused from the vacuum leak I have behind the HVAC unit? When i fix the hvac unit, will this fix the cruise control problem?

 

if the cruise control is vacuum actuated then yes, the HVAC vacuum leak is causing the cruise control problem

 

I know my cruise control didnt work the one time I forgot to re-attach the vacumm tree to the back of the Intake Manifold, back by the Dizzy.