Looking for any help that can be offered.

2002 C5 Stick Base Model

About a month ago the car would at times start and run rough and sometimes die upon start up. Very random and about 1 of 4 starts. After observing the gauges when this occurred I noticed that the voltmeter was reading "0" or close to "0" and it would then normalize after about 30 seconds and the car would then run fine.

I sent the car to a shop and had the alternator replaced (at the suggestion of the shop) and note that the battery and alternator appear to function correctly. I now am experiencing the issue again and more frequently. The car at times will turn over fine but fail to start (when this occurs the voltmeter reads low, the gauges do not cycle correctly, I do not think I hear the fuel pump prime and now I am hearing a clicking noise from the passenger foot-well). Today the car did this again (started but ran rough) and I got the full run of error codes (low engine power, traction control etc.). I cleared the codes and the car started normally and ran fine.

Any thought as to what this may be? Note that the car runs fantastic and this erratic issue is driving me crazy.

Thanks in advance for any advice and if I can offer a better explanation or expand upon what I am experiencing to help with suggestions please ask.

CRM