miss while under hard accelleration

Last weekend I changed the stock fuel pump for a 255 lph unit, changed the spark plugs ( one step colder than stock, I am using nitrous.) and changed the spark plug wires. When I accelerate moderatley or hard there is a miss, the miss is not present under normal driving or at highway speeds. Any feedback would be great. I checked the wires and connections to the plugs and all looks good.

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describe it better. is it a jump or jult (sp). does it like sorta cut out and just llike spring forward and take time to come back. if so then check all your sensors and realys and replace em.
I did not mention but my car is a 92 lx 5.0, It is hard to describe, but here goes: dead stop take off then at about 2500-3000 rpm it feels like it is cutting in and out slitely, does the same in second gear(AOD). Is it possible the fuel filter is dirty?
If your injectors are old and tired that could be a problem. I had a similar problem on my 88 GT that was curred with new injectors. Not a fun project but it was time. Changing the fuel filter is always a quick and easy part of the diagnostic process. Are you able to measure fuel pressure? Maybe something is up with this new pump. Is it still missing at high rpms? Or does it just miss when you mash the throttle at low to mid rpms? When my injectors were shot it would still rev pretty godd a high rpm but would miss and bog when I mashed the gas at low to mid rpm. I'm not an expert at NOS, so I'm not sure how that plays in with it.

Let us know how it works out.
mine was doing that a few weeks ago and then would actually cut out for like 5 mins it ended up being my ignition madule ur best bet is to bring it to a diognostic center and have them find out what the problem is then u can fix it ur self
Mine does the same thing!

I just changed the spark plugs and wires on my 94 5.0, and now whenever I romp on the gas, it just doesn't go anywhere! It drives fine normally, but if you drive it hard like I do, then it craps out. Anymore advice? Maybe my injectors are bad? Thanks all.
You have crossed some plug wires, or some of your plug gaps are wrong. If thats when it started, right after the tune-up, then thats what caused it. Very unlikely that something else decided to die at that time. I had a coil die once, the day after I changed plugs and wires, but it was running fine right after the swap.

edit: do you have the HO firing order? If not, 13726548 is for HO. 15426378 is non-HO. Rotation of the rotor is counter-clockwise.
Try moving the #5-6 spark plug wires away from each other. From the cap down to the plugs. You may have ignition crossfire. The symptoms you describe sound just like my car. Seperating these wires cured mine.