whenever i turn my truck off it makes a buzzing noise. i think its done this since ive had the truck. the other day, right after i turned it off i tried to listen to where the buzz was coming from. i unplugged the green vacuume line that goes into the egr valve and it stopped. i plugged the hose and it still didnt do it, but once i plugged the hose back into the egr valve, it started buzzing again. it usually buzzes for a good 2 or 3 minutes. truck in sig

 

Bad EGR valve.
The diaphragm has a hole in it.

 

ok il have to purchase a new egr valve. should be an easy fix. thanks!

 

Not to hijack, but if I pull a vacuum to my egr valve,
it will do a suction/buzz/chatter too.
but not when I shut the truck off like octaneforce.

Maybe mine leaks faster.

Wouldn't it be nice if that was my gentle miss problem?

Thanks

 

Neither one of you all should have vacuum on the green vacuum line at idle.

So I would get the vacuum problem fixed first before you either of you replace the EGR valve. Yes vacuum on the green line at idle will cause a miss.
I would look at the EGR solenoid (EVR).

I would also pull the codes on both trucks.

 

ok, Thanks.

So the egr valve should NOT buzz when suction/vacuum is applied manually?

just sitting there, engine not running.

I would think it (well the whole vacuum line system) should hold vacuum for a while, at least?