I recently replaced the purge solenoid valve after it tripped a code. Shortly thereafter I noticed a clicking sound while at idle or at a stop light. Sometimes it's not very noticeable, sometimes more so. It's not a loud clicking sound but definitely enough to warrant concern. Any ideas on what is causing this? Could it be installation error? The installation was pretty simple and it was hooked up carefully, exactly the same way the other one was. Thanks in advance for any help you can provide.