My mac solenoid would tick when i would turn the key to the on position and would stop when the car was started.Now its startig to tick when the car is running.Is it failing or is there some test i can do to see if its bad?

 

What are you using to control/drive it? If its ticking that means its working.
With my AEM I had the output only active >5mph so it was off when not moving, it was so annoying.