DPFE/EGR valve pressure sensor

I`ve attached a pic, On a 2004 Impala, is this a Egr valve pressure sensor and if it is, who sells them and are they expensive? Autozone and Oreillys didn`t have a clue.

Your vehicle has a linear egr valve, no backpressure sensor. The part you have circled is the canister purge solenoid.

Thanks!
No wonder I couldn`t find the part, I had the wrong name of it from an autoparts store (which will remain nameless, maybe). Do I really need it or can I unplug the electrical connector to it and drive it with no problems?

What problems are you having? Is the SES light on? Are there any DTC's in memory?

About three weeks ago, I started hearing a small noise under the hood that sounded like a faint knocking. Sometimes when the car is idling, I hear it. I traced the noise to the solenoid and when I unplug the electrical connection to it, the noise stops. Not having any problems with it yet, just couldn`t figure out why it started the knocking sound.

The ECM activates the solenoid when certain parameters are met. It can come on pretty much any time the engine is running. When the ECM runs the monitor on the EVAP system, and the test completes, if there's a problem with it, the SES light will come on. When there's a problem with the EVAP system, you most likely will not notice any difference in engine performance. Bottom line... if it ain't broke, don't fix it ;)

You have a point about the "bottom line". Thanks for the help.