humming noise from engine when starting cold. faulty idle air control valve causing noise,can tap on valve and noise will go away. must replace valve to fix.
Problems for specific Ford Expedition years:
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Newest reported 1999 Ford Expedition problems
There is a technical service bulletin for the V8 engines regarding a possible problem with the spark plug being ejected from the cylinder head, damaging the threads in the spark plug hole. If the vehicle is under warranty, cylinder head replacement is recommended. If the vehicle is out of warranty, Ford authorized the use of a specific thread insert to repair the head.
Intermittent rough idle may be caused by the EGR sensor sticking, causing the EGR valve to stay slightly open. Our technicians tell us the valve and sensor must be replaced together to correct this concern.