Ticking noise

I have a 98 Cherokee 4.0 litre 5 speed. I have noticed a ticking noise off and on for some time and questioned if it was the engine or what. I come to find that its a solenoid mounted on the firewall and there is a tag that says evap. At idle the solenoid is clicking in time. Doesn't do it all the time but more often lately. Can anyone help me with what is going on and what the fix is. Thanks.

There most likely is an intermitant problem with the hold-in windings on the solenoid. Just go get a new one.

There most likely is an intermitant problem with the hold-in windings on the solenoid. Just go get a new one.
I was checking it out the other night and it could be the problem, thanks. I will check it out with a new one.