P0171 Ford - what should i check after i changed the air mass flow sensor

Question

Ive changed the fule pump ,and the fulter ...and i changed the maf ...what do i do now ...and the truck feels rough now then before ....

Answer 1

P0171 Fuel trim lean Bank 1

Vacuum leak has to be looked for. Some of the most popular are the plenum gasket upper and lower.

 Plenum gasket such as this are the most major contributor for a lean condition

Both the upper and the lower are the common place for vacuum leaks to occur