1998 expedition 5.4 throwing PO171 and 174 code
 

Ford just failed emissions testing, throwing a PO171 and 174 code. Is there a cheap fix I should try before taking it to the repair shop? The check engine light was on and now it is off after pulling the battery cable.

There is a vacuum line that goes from the rear of the intake to the pcv and sometimes tees to other lines. It gets soft and rots at the intake manifold. It is hard to see but you can reach your hand around and feel it. If it is soft it is probably leaking and giving you a lean condition. Check that first.

Btw just disconnecting your battery while does temporarely erase the codes it will still fail emissions because when they test it the computer will have a p1000 code that tells them it has not passed all its on board test yet, ie you disconnected the batt, so it will still fail

Thanks for the tips.