Good Morning All, I just finished taking care of the same problem. Turns out to have been a vacuum hose that had a pin hole in it. The particular hose was running down along the EGR pipe and then to the HVAC unit. Of course it was in a spot on the fire wall that could not be reached easily. This pipe had been touching the pipe and was burnt. Ford was going to charge me over $1,000.00 to troubleshoot and repair it. I paid the $65.00 service charge and said no way. So, I spent a little over two hours tracing and testing vacuum lines and spent $1.81 for a new tube.
