Hitting a Rev limiter at 4.5k

[AZ_z34]

Hello, hoping someone can help me out and figure out what the problem is…
Recently my 09 Base 370z started acting funky, I can hard accelerate perfectly fine until it hits 4.5k - 5.5k RPMS before acting like it’s bouncing off a redline…
Then if I manual shift it once it starts bouncing it does a pop like as if it’s tuned but it is not.
I just put another used fuel pump in to see if it would fix the problem and it didn’t, it only fixed my faulty fuel gauge issue from the bad fuel sensor.
One thing I noticed is when I disconnect my battery and let the ECU reset and reconnect it, it runs perfectly fine… I can go all the way to the actual redline no problem. I can drive it for about an hour before it starts acting up again.
I have a Tomei exhaust but it is missing a gasket as I thought I lost it so I put it together just like that until I could get a new gasket… could that be an issue?
I thought about cleaning the MAF sensor, throttle body, injectors or maybe the spark plugs aren’t giving enough spark as I haven’t replaced them since I got the car and it’s used with 89k miles now 112k. I just need someone’s opinion on what it could be

Thanks for reading.