hey guys so my glanza has a dead spot. when im at low rpm at like 2000 or lower and floor it, the car slows down like somethings pulling it from the back then boost kicks in and its off. ivd got decat blitz ecu magnecores. it started last year. when crusing at 30mph in 4th i can feel theres a misfire. changed coil pack 2. doesnt use oil or water. what can cause this because it started out of the blue and dont know what it is. please help