I've heard the install torque on these solenoids can be very important also. I cleaned mine and it seems to be OK, but I have thrown a cyl 3 misfire intermittenly. I logged AVCS left and right for days on end and never found a problem. Quit logging and it threw a code-LOL. Typically more AVCS advance is called for at lower rpm/higher load situations. The solenoid fails to move on one side and you get a misfire code. I am still getting a rare cyl 3 misfire once every 3 weeks or so that I feel like is related to this solenoid, but I hate to throw money at an issue without being 100% sure.
For those with Cobb you can log both AVCS left and right, they should stay pretty close together with 2 degrees of each other at all times. If one side lags consistently in degrees of advance, it's probably the solenoid (or the banjo filter to the solenoid)