So, over the past 100 miles, I gained an annoying clicking sound. It sounds similar to a fuel injector. It only does it at idle. As I was listening, i narrowed it down to this little gem:

(Dead center with the loom/plug and the vacuum lines going in one side and out the other.)


It's some type of vacuum solenoid. I further diagnosed it by unplugging it and the sound went away. It seems to be part of the EVAP system, but not sure exactly. I already made an appointment because its still under warranty, though I'm just curious at this point. Any ideas?

 

Sounds like a "vapor pressure sensor." Happened to me in Sep 2010 with 23,000mi on the truck. Part #: 9U5Z*9C915*E was replaced and ticking went away.