One problem related to rear suspension springs/bags has been reported for the 1999 Ford Expedition. The most recently reported issues are listed below.
: the contact stated while driving 55 mph, there was a noticeable bounce in the rear of the vehicle. After being taken to a private repair shop, it was determined that the rear air suspension bags were deflated, and there was no air getting to the suspension system. There was no leak found in the bags, and the mechanic was unable to determine the cause of the deflation.