I just found a vaccum line not connected while looking for a cause of poor fuel mileage. Could this be the cause? The only thing I have noticed that might have been vaccum related has to do with my pac brake. It had been slow to engage for a while.There had been no ac/heater issues or regular braking problems. I reconnected the vac line and the pac brake is much stronger. Anyone have a link to the vaccum line diagram for my 98.5? I'd kike to know what that line did.......or does?

 

As far as I know the vac system only operates the cruise control, the HVAC doors, and some exhaust brakes like yours. I can't think of anything else it might operate?