This is very common concern, you will need upper intake manifold seals and Bolts, there are seals around the bolts! Tsb is below.
This article supersedes TSB 05-17-3 to update the vehicle model years and issue.
Some 2001-2003 F-150, 2004 F-150 Heritage and 2001-2003 E-150/250 vehicles equipped with a 4.2L engine may exhibit the malfunction indicator lamp (MIL) on with diagnostic trouble codes (DTCs) P1131 and/or P1151 (system too lean bank 1 or 2). This condition may be due to leaking isolator bolts/port gaskets in the upper-to-lower intake manifold mounting area. This condition is sometimes intermittent and may not be apparent on a warmed-up engine.
Refer to the following Service Procedure.