I just bought a 2006 Lincoln Navigator (same creature as the Expedition with 5.4L engine).
The previous owners put a slick aftermarket CNG system in it...when I run on the natural gas it costs about $20 to fill). I love that aspect of it, but I've had a few problems. Yesterday, I loaded up the kids and started driving when I heard a very distinct clicking noise. Figured out that it was under the panel of the passenger side rear wheel well. I have a pic of the part...only thing I could do was unplug it. Once I did so, the car still ran but not very well. Can anyone help me understand what the part is and how to fix it? The clicking was from the plastic gear that was trying to turn but was stuck for whatever reason. There are a couple of additional things, but I'll save those for another post.
PLEASE SEE THE PIC I TOOK....

 

Couldn't add a 2nd picture of the part...so here it is

 

Welcome to the site..

It's the Blend Door motor..