1998 Subaru Outback Sometimes doesn't start

A month ago tried to start car and nothing happened but there was a clicking noise at first and then nothing. Was able to get it jumpstarted. Took car to Subaru and they replaced the 2003 battery and alternator. A week later car would not start and could not be jumpstarted. Had it towed to Subaru and they said it was a wire that came loose and it was a grounding problem. A couple weeks later now, I start the car in the morning and nothing except a click sound somewhere under the glove box. I turn the key again and sometimes it tries to start, turn the key again and it starts. I drove 4 miles to the store, came out and the same thing: turn key and no start, turn key again and it finally starts. Help! Any ideas? I have an appointment with Subaru again but they obviously haven't found the real source of the problem. They say they've run a scan on the car.