lsxTAlemy

iTrader: (2)

guys i have an ls2 z28 built for nitrous. motor built by a supposedly reputable local shop. has forged rods and pistons on stock crank motor was balanced . vibration comes in at 2k leaves and come back at 4k then leaves. full throttle it doesn't happen. only does this when u hold the rmp on at that rpm. the shop guy told me to double check the crank pulley. so i changed for a new one.. told me to tune it. i tuned the car now hes telling me to check for miss fire or flex plate. changed out plugs, wires and swapped coils. separated the trans for the motor and the vibration still there, but less noticeable. with the trans on it amplifies. i changed the flex plate last night and nothing.

what are you guys thoughts. what u guys think i should check next.

the car performs well, runs real strong. but the vibration has me worried... motor is supposed to hold well over a 300 shot in one hit with out braking a sweat...

thanks in advance