Could someone explain to me why there would be a 1-1.5 ms difference in the pulse widths from the left to the right bank of my engine at idle?
In a 1995 LT1 Heads/cam combo. Racetronix 37lb injectors, PCM for less tune? They equalize during accelerating.

 

The BLM's (long term fuel corrections) on one side are significantly higher than the other side. "Split BLM's" are not uncommon with a decent size cam or with an aftermarket throttle body. Or it may be a problem with misfires or an exhaust leak on one side, causing a "false lean" and driving the long terms up. If you are scanning it to see the pulse widths, you should also be able to look at the long term fuel corrections for Cell 16, the idle Cell.