Test codes 171 & 174 came up said it is running lean how do I fix
Friday, February 22nd, 2013 AT 4:52 PM
1 Reply
WRENCHTECH
MECHANIC
20,761 POSTS
On a Ford that is nearly always a severe vacuum lean. Listen for a hissing noise when idling and follow it to it's source. They are notorious for sucking holes through large rubber connectors and PCV hoses.