I went looking through an old Haynes manual and your pic kinda resembles a vacuum solenoid for the EGR system. Did you follow those vacuum hoses back to something?

 

i think your right there, would you happen to be able to upload a pic from that book? i just want to know why its making that noise and if thats not the cause of some of my cold start and idle problems maybe thanks for looking

 

Sorry but I had some trouble trying to load pics but remember it only "resembled" it so it may not be important. But what I did see was something about a canister purge valve / solenoid. Assuming that your year of vehicle had one, this sounds similar to your situation with the clicking.

http://www.2carpros.com/questions/19...ruck-emissions

In the Haynes manual it was a diagram of a typical vacuum hose routing for a V8 engine EGR system. As far as the egr vacuum solenoid goes the item I saw looked similar to the bottom "solenoid" in your pic but mounted on a bracket off the passenger side of the valve cover. It was a cylinder with a little square piece on one end and 2 vacuum lines on the other end. One was routed to a Tee going one way to the vacuum amplifier and the other way to the back of the carb or manifold vacuum. The other vacuum line led to the egr control valve I believe. In the general description it says that most vehicles are equipped with a delay system using an electrical timer mounted on the engine compartment side of the dash panel. The timer controls an engine mounted solenoid that delays EGR operation for 30-60 seconds after the ignition is turned on. It gives instructions how to check the vacuum solenoid if that is it.

So the big question is if the vacuum lines go to the vapor canister or to the EGR or none of the above.

 

I found a two pictures in a Hayne's manual of exactly what you have. It is an EGR solenoid. The pictures I have show it mounted on the firewall and a voltage regulator is also in the picture so that dates the system to prior to 1988. The only problem is I can't think of any reason for this to shock anyone.

 

I went to a pick-n-pull yard on Sunday and there it was on an 87 D150. 2 vacuum lines were cut but they looked like they went to the top 2 positions on the manifold vacuum "F" tap. The other 2 lines went to the smog pump and the front of the carburetor. There was a couple of electrical plugs going to the solenoid. Don't know why it should shock anyone like SEAL said. What did he touch it with - his hand or a screwdriver? If a screwdriver, maybe it arc'd on a positive and ground. BTW, it was located on the fender just under the passenger side hood hinge - just like yours.