cep623

I have a 2000 Milly with a 2.5 ltr with 287k for the past 3 months I've been having an intermittent problem with it starting. I'll go to start the car and all I get is one click from the starter, the on the second or third try it will start like normal. this has only happen 4 times in the past 3 months. I'm not sure if it's the solenoid or the relay for the starter...or something else. any help would be great, thanks in advance