If you have P0171 and P0174 and a check engine light that is causing you to want to replace the intake gaskets, please refer to Ford Technical Service Bulletin 03-16-1 which will tell you about some other items that need attention... Just a hunch.
the upper plenium has an upper and lower. the other lower is the actual intake manifold.
The uppers pay 1.9 hours in labor and 34 in aprts. common failure for code 171-174.
the lower intake pays 2.8 hours and add on coolant flush and oil change. not a common failure.