code 171 and 174 come up , runs great, but need to fix to get inspect

It means fuel lean condition on banks #1 & #2. Change your fuel filter, first choice. Next have it tested by a professional you trust for fuel trim diagnostics. Auto Zone will sell you some o2 sensors.

Have replaced loads of intake seals and the intake bolts on these. start the van cold,pour water over the intake and listen to the gurgling noise,that's water getting sucked into the intake via the faulty seals on the bolt washers and intake gaskets. VERY common!