Car Hesitating at 6-7k rpm
 

Hey guys, i have a JDM auto rx8.
recently it was giving low mileage. It came down to clogged cat. I gutted it since getting a new one was out of budget and we do not have any laws enforcing us here to use it. I will get one as soon as i can afford one.
car has new spark plugs and coils changed 5000km back.
the problem i am facing is car hesitating at 6 to7k rpm. I mean it goes beyond that but it kind of goes up in a jerking manner. For example car will lose power at 6k. Then jump to 6.3 then again lose power then jump to 7 and this goes till 8k rpm. Thats when i hear the pop.
i have driven 500km no cel yet for cat.
what may be the problem (obviously gutting cat lead to it) and how can i tackle it.
​​​​
39000 km on the odo

I am suspecting
Sicky SSV
Bad fuel quality (changed fuel station)
Spark plugs (but the acceleration and below 6k drive is good to go)

Update
 

It fixed itself. I believe sticky ssv. I kept the accelerator floored. Rpm is smooth af now