my car is jerking and shifts in to neutral what could my problem be? on 2006 Chevrolet Impala

i have understood that by putting in an aftermarket stereo without the module sometimes the comp. starts to act funny could that be my problem? that happened to me when i put different size tiers on my car when i took it in all they did was reset the comp.

Asked by for the 2006 Chevrolet Impala