if you had your car running fine before installing this pump,then i think youve done something that you shouldnt of.
The pump itself should be ok if that was the only thing installed.
Even if higher flow,the regulator is the part that controles the amount of fuel pressure your injectors will see,and will keep it at a constant 40-45psi at idle.
unless your regulator is faulty,it could raise the pressure and make it run richer(but you havent touched it,have you?).
Best thing to do is,put a fuel pressure gauge in line with your fuel out hose and see how much PSI your getting,and let us know.
Have you connected everything properly?(in -out lines)
once started,can you rev it and keep it idling
explane a bit more...