NC Purge Evap Valve Clicking

Technical Area Engine, Transmission, Exhaust etc
1
  1. My model of MX-5 is: __MK3.75
  2. I’m based near: __Swadlincote
  3. I’m looking for technical help or recommendations on: __ Purge Evap Valve

Got a little issue my purge evap valve solenoid starts clicking at idle after around 20mins of driving it stops if i unplug it, the clicking stops or if i turn the engine off then on again it goes away.

Not overly worried but when you first hear it you think its the rods doing a knock knock joke.

I did swap it out for a second hand unit but still doing the same thing.

Any Ideas?