I am experiencing severe misfires under load when getting on the throttle hard. Engine revs cleanly when in neutral. Engine is a 350 tpi with new injectors, plugs, wires, dizzy, coil. It looks to me to be ignition related but all of my ignition is new with less than a couple thousand miles. The distributor is a remanned from oreillys so not the best and also the ignition coil. I don't believe it started happening until after I installed my b&m megashifter but I really don't think any of that wiring could have this effect. I could be wrong though because also when I shift from N to D or N to R it will flash the SES light and stall unless I shift somewhat fast. That could be totally unrelated though. I took a video of the misfires. Anyone have any ideas what might cause this? All help is appreciated!