I need help

[TRD SPEC]

Hi,i'm new to the both this page and the car world,i have a tiny knowledge about car and always wanted to mod car just for the sake of fun.I've done some mod on it and heres the list of mod that i have done.
[The car is a vios ncp42,the engine is 1nz-fe..automatic,stock engine no tuning]
1.4-1 performance header
2.cat remove
3.2 resonator [1 of the resonator is smaller than the size of my cataltic converter and the other is about 3-4 inch smaller than the stock's resonator]
4.s-flow high flow muffler 2inch inlet and outlet
5.custom exhaust piping[2inch after the header and 1.6 after the resonator]
6.Short ram intake[its a diy project i used a samco hose to conect my throttle body than to a air flow sensor adapter]
7.1zz-fe throttle body[60mm]
Comparing to the stock
Stock did 0-100 in 12.3
Now did 0-100 in only 9.9[woah....i was suprise i test it for almost a hundred time and still did around 10 second the best so far is 9.9]
But the problem now is every time the car swift from 2nd to 3rd theres a huge lagg in power especially after 140km/h it stop for a few second than it accelerate back and happend again when i reach 160...could it be because of lack of back pressure because the piping i'm using is too big for a automatic transmission car or is it because of the throttle body being to large?Or maybe the car haven't been properly tune?

[rabbito]

same here, i started off by installing full exhaust and intake/TB like you..high 9 to low 10 seconds...
i know what you mean by something weird..lol...switch through gears 1->2->3->D, rev all the way through 6000rpm

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