WARNING: This page is about a different car, the 2004 Ford RV Cutaway, 2004 Ford Econoline, and 2004 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
Special Tool(s)
Fig 1: Identifying Special Tool
Courtesy of FORD MOTOR CO.
Place a straight edge across the exhaust manifold flanges and check for warping with a feeler gauge.