I have a knocking coming from my motor and I'd like to get it fixed. I believe I've located the area it's coming from but I'm not sure what it is. It's the two black pipes that run parallel on the top of the motor on each side of the throttle body.

 

I think those are the fuel rails aren't they?
I haven't heard of fuel rails knocking before...

 

my truck starts knocking after I turn it off

 

that's probably just metal contracting while it's cooling off

 

There's avalve one one of them almost like a tires valve stem and I gave it a quich push and a cold liquid came out and was almost aerosol like. Leads me to believe it is ac? I can post a picture of them if needed

 

I would just to help out...your lucky if all you did was squeeze it and got a cold feeling. I had a friend that didn't recharge his ac right and got instant frost bite on his finger tip...wasn't funny then but the next week it was histarical!!!

 

the A/C lines are raw metal (that dull silver color) the fuel rails are painted black, i think you are talking about the fuel rails, but post up a picture to be sure (also look for a line or hose connecting them, around the front of the intake)

 

Like RollerRed said, those are your fuel rails and they are running around 50-60psi so the little valve you pressed (the fuel pressure test port), the rapid decompression of the fuel into the atmosphere caused it to atomize and drop in temperature.

 

you definitely shouldn't go around pressing those valves on the ac or fuel system unless you know what you are doing. they are under high pressure and for the ac very low temps and can seriously hurt you

 

alright heres a pic. and i didnt press it with my finger that_guy. i have some common sense lol.
its the black rod going right up the center starting at my fingers