Injector Question

[IndyNova]

have a quick question, I currently have gt-500 injectors
(66#/hr @ 58psi fuel pressure) in my 6.0, that has a "start-up" tune in it. When I start the motor, it runs for 5-10 seconds before it starts popping and backfiring. My tuner wants me to put some street miles on it prior to the dyno to work out the bugs. Would having the bigger injectors installed, and say, the stock injectors parameters in the tune cause this? Thanks for any help/advice you guys can offer.