ZHP NA Project - More Power

[Newjack]

I put back the stock headers because at the moment i am trying to find the issue that causes:

1. At 1500 rpm when in 4 5 6 gear and i fully press the gas pedal the car jerks for about 1-3 secpnds and then accelerates
2. When accrlerating at 4 gear i can hardly reach 6000 rpm and i. 5 gear i cannot go past 5000 rpm no power
3. When i redline at neutral it misfires in the muffler
4. At idle when i turn ac on the car starts jerking


My assumptions

1. Fuel pump
2. Coil
3. Injectors


It must be either of these what do you think ?

P.S. ebay headers are a must mod !

Sent from my SM-G925F using Tapatalk

Coils and plugs would show symptoms at idle or low RPM's right?

Maybe fuel pump/filter if its old or a failing injector?