Sometimes my car seems like it's stuttering. When I accelerate, it seems to hold back or stutter below 3.5k, and then after that it opens up nicely, but this symptom seems to be amplified when my JWT intake is on. Because when my normal airbox is in place, it doesn't do it as severe, could it be my MAF sensor? TPS? O2 sensor(s)? Vacuum lines? Fuel injectors? I changed out my fuel filter and that didn't help at all, could it be the fuel pump? I also added one of those fuel injector cleaners which seemed to have helped very slightly.

What do you think is my problem?

Also this may or may not be related, but when just idling, the idle seems rather rough at times, and when I turn the steering wheel when when stopped, the rpms will drop then climb back up, it also does this sometims randomly when at traffic light when I'm at a dead stop.