[DRW1000]

It sounds like the tech at Ford is providing conflicting/confusing information.

If he remembers the lean codes then yes they are the infamous 171/174 codes. The TSB states that if there are no other driveability concerns to go ahead and perform the TSB.

The lower intake manifold gasket could mean the port seals that are on the top of the lower intake or it could be the lower intake to block gaskets. Both could introduce the lean codes. I would suspect that the intake to block gaskets would provide other problems. Oil should not really be pouring out of anywhere.

I find it hard to believe that replacing the lower intake to block gaskets could cost less than the ports seals since more of the engine needs to be disassembled including the ports seal area to get to them.

I would recommend going back to Ford and ask exactly which part is going to be replaced (part number would be the most beneficial). Ask why the TSB is not the cure since you do not have other drivability issues (I assume that you do not).