from Where you swapped your engine is a good known parts dealer, he is my classmate. you must activate the VVT. and your CAM sensor error code must be cleared. you have to change CAM sensor wires. and the cam sensor position for VVT 1.3 is different from the pakistani 1.3. your car is currently on limp mode due to cam sensor error. thats why you are facing problems. if you replaced ECU as well then you have to change cam sensor blue wire from 11 pin position to 14 pin position in the ECU grip. if engine timing is out even by one tooth you will be facing cam sensor error code and limp mode. in limp mode your car is under powered with more fuel consumption, black smoke, fluctuating idle RPM, and top speed of only 80 KM/h.
whenever ECU encounters cam sensor error, it activates the limp mode in which all the four injectors are fired at once means firing simultaneously and NOT sequentially.