Thanking you so much atta brother, finally I have been able to resolve the issue. It?s surprising, that I highlighted this to many people including the lead mechanic at many Toyata motors but they flatly refused that problem be with variable resistor even-though I told him that?s the only thing which is left and being suspected but he insisted on working on parts which already been verified. I have searched everywhere, but found no answers, help or clue. I wonder, how many mechanics must have ripped the poor owners on same vehicle as I find none who even had a clue to this and I already spent a lot on same things over and over again.
I was able to remove the variable resistor, find 5 volts adopter for powering the sensor, first measured the resistances which turned out to as follow while comparing it with document, I suspected the problem until I connected it with 5volts adopter.
VC to E2: 4.52k Ohms as compared to range of 3.5 to 6.5 Ohms as prescribed in manual
E2 to VAF: 1.02 k Ohm as compared to range of 0 Ohm to 5kOhm
VC to VAF: 3.6 k Ohm, range not prescribed
But once, I connected it with 5 Volts adopter then voltage varied from 0 to 4.55 Volts so knew that the part to be good. Voltage decreases once moved towards R and increased once moved towards L. Found the initial value on resistor to be 0.8 Volts but adjusted to 2 Volts and modified the wirings for testing on car and once connected the problem was already gone and car was rocking. Information, you provided on phone was very helpful such as that it comes from factory with preset value at 1.23 Volts and adjustment to 5% per 50,000km so later, started decreasing the voltage till I brought it to 1.3 Volts as found the RPM to be more stable on this and near to that with CNG. Took the car on drive, able to climb up on a hilly road, stop in-between and still able to move without even a slight hesitations and these were the things I never imaged doing before on petrol, now such tremendous power this car had.
I will further test the vehicle and will keep you informed regarding its status. I hope, you will enjoy the pictures I have taken while testing this, a big thanks to you and a way of hope to others facing similar issue.