I was driving to the mall last night and was driveing pretty hard(takeing revs to 5500 rps). i stayed for about 20 minutes and then left but when I started it and drove away my engine felt as though their was a cylinder misfirering. it would stutter up to about 3500 rps and then stop stuttering but would feel like their was barely any power. I checked all plug wires and they were connected. I have no clue what could have happend, i installed an intake a few days ago but i don’t think that it would affect it. i reset the ecu today when i got home and it felt like their was a little more power but not as much as their was and it still stutters. i could use any help or advice.
check to make sure that all the hoses and gromets are installed properly on the new intake.
I just added a K&N filter on the end of the stock intake pipe
ok, well then i don’t know 
then again, i never really DID know. 
When is the last time that you did a tune up?? If it has been a while, or you dont know, then you should change the spark plugs, spark plug wires and cap & rotor. That would be the best place to start.
The only other thing I would check initially would be the O2 sensor.
Later,
BR