Fuel Consumption you can work on if all your sensors are properly connected and you dont have any engine codes. You will have to dig into this wiring issue to solve it properly.
The wiring you got was it uncut or half cut and made by your electrition?
R u sure its a 4AFE engine or 5AFE? as its very very rare to find 4AFE used imported in Pak, Most of them are local used stolen or rebuilt ones. You can check that by looking at the Engine No.
CNG quality in Lahore is pathetic i remember my Corolla 88 with 2E use to give me 160+ In isb but when I went to lahore it gave me no more than 75KM. There are better cng stations in Lahore try that like i heard ones in Johar town are better hmm not sure.
First you have to connect check engine light in your car. If you dont have check engine light what you need to do is find a small bulb connect its + to battery positive and negative to W wire coming from ECU. You can open up your ECU all the pins are labeled so you can find the W pin.
If you have diagnosis box in your wiring after check engine light is connected you short TE1 and E1 in diagnosis box and switch the car to IGN and check if there are any codes. If the light keeps blinking everything is fine other wise it will blink in a sequance to tell you about code. For Example Code 42 it will blink 4 times than a delay than 2 times. Post the codes here for solutions 
Diagnosis will be in the engine area with wiring.
