sometimes it starts sometimes it doesn't

I have a 96 grand prix se with the 3.1 engine. I have had alot of problems with the car not starting. At first it had the security light on so I thought it might have been the pass key 2 security system. It no longer does that though and i've taken the car to a pontiac dealership and all they told me was that my starter was bad. I just replaced the starter a couple months ago and it works most of the time. Can a starter work sometimes and not other times? I have had a new computer installed, got a new starter installed, and i'm kind of clueless. My friend says its not the starter but pontiac said that it was and that they hit it and it started up. So my question is can a starter act up intermitantly? A few days later we hit the starter and it fired up and then shut it off and it started again. About 20 minutes later it would not start again and hitting the starter again took care of the problem. I bought another starter and had it installed. It worked and then acted up again. I have been buying parts at autozone and was wondering if 2 starters in a row could have both been bad. Autozone checked the old starter and even said it was good....

Any electrical component can fail intermittantly. The fact that you can tap you starter and make it work indicates that the starter is bad.

In my opinion, the first thing you should do is remove the remanufactured AutoZone starter and throw it as far as you can. They are SHIT.....as are their other remanufactured electrical parts (starter, alternator, wiper motors, blower motors, etc.) I've worked on cars, professionally as well as shade tree, for about 22 years. My experience has been that the quality of AutoZone reman. parts is very low.

Buy a new or reman. starter from Napa or CarQuest.