After having my engine replaced there is a strong fuel smell coming thru the vents. I have had it back to the dealer twice and the first time they couldn't find anything wrong. Second time they cleaned the evap system and an air chamber. Not sure what that means. Well I thought they fixed it but it's back. Any ideas? If I turn the recirc on the AC it goes away.

 

Tell them to look up a TSB for the E150 and E250 vans with the 5.4L. There is a TSB on them about a leak from fuel rail or something like that. There is certainly a fix for it. Do a search of the forum and there is a huge thread on it.

 

Usually, that's from loose spark plugs.

 

Yup, happened to me...and it works when i tightened the sparks.