Is there an easy fix other than installing a valve on the heater hose?
Thanks,
Dennis
Sounds like you may have a vacuum leak. When climbing hills vacuum will drop even more. How about A/C? Does the air duct flip from front vents to the defrost or heater vents when accelerating or climbing hills?
Yes. Where is the most common location of a vacuum leak?
I'm not sure. Any vacuum line around the battery would be suspect. Corrosion from the battery quickly deteriorates lines running nearby. I know on Dodge trucks the cruise control module is mounted under the battery and the vacuum line running to it is very common to leak. I'll have to take a look and see what might be a common place to look on a Ford.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.