Whenever I shut my motor down, there is a buzzing noise that can be heard coming from what I think is the EGR valve solenoid. It is a black cylinder shaped part close to the throttle body in front of the DPFE sensor. It has an electrical connector w/ two wires going into it and two vacuum lines connected. I'm in the process of trying to defeat my pinging problem and I just want to eliminate the possibiblty of this solenoid being defective. Is it normal for them to make a buzzing sound for up to 10 seconds after the motor has been shut off?

Scrib

 

I am not for sure if this makes it normal but mine does the same thing. At first I thought it was pressure bleeding off in the cooling system but found out quickly when I popped the hood. I had no idea what it was until many months I checked to see what it was. From what I read it is part of the DPFE and EVR the controls the amount of flow to the EGR. I would almost guess what we hear is perfectly normal.

 

It's pressurized fuel from the return line going back to the tank

 

I really don't think what Scrib is refering to is in the EVAP system. I think he was tlaking about the DPFE and EVR solenoid. It sits on the dirver side toward of the front throttle body and the TB cover even has a cutout for it. On the top of it, it looks like it has an adjustable **** but if you try to turn it, it will just spin forever. Scrib is that what you are talking about?

 

KYFordFreak - I'm pretty sure you are right. I think it is the vacuum being released from the solenoid you were referring to.

One time I removed the vacuum lines from that solenoid and shut down the truck and didn't hear that sound. There is a similar looking solenoid near the brake booster (at least on my '98) that might make the same noise.

 

The thing above the brake booster does have to with the EVAP controls, it is a vapor management valve. The PCM actaivates the vlave allowing fuel vapor from the canister to the intake to be burned.
The only one I ever here is the EVR solenoid. My problem is I have a abnormally loud rattling PCV valve and do not know what's causing it. Any ideas?