evap. valve / stuttering

[wade623]

Mk4 2002 1.8

So lately my car has been stuttering at idle a little bit so I thought it might be a vacuum leak so I was looking for cracked / broken lines and didn't find anything so I started the car and stood there with the hood open and waited for it to start doing it, so it did do it and it only seemed to do it when the valve stopped clicking for about 1-2 seconds and start clicking again and then runs fine until it stops. It is fairly regular in consistency so I was wondering if anyone has any thoughts on what would cause that.
I have changed that valve before so it is aftermarket so it could be a possibility that it is a bad one???.
I also checked for obd 2 codes and nothing came up but when it went bad the first time I beleve it was p0444 and would cause it to take a long time to start or not at all.