Throwing no codes still dropping Rpm! help

[imran.niaziccl@gmail.com]

I own Yaris 2012 manual transmission and from a couple of months I am facing a problem of dropping RPM which only occurs when I switch on AC.I live in Riyadh which is hot throughout the year. I did computer testing and it was showing the code for a faulty throttle pedal sensor which I replaced with new one and also replaced Airflow sensor which resolved the acceleration problem but dropping RPM still remains.Car, when driving in traffic and pressing clutch, drops rpm to 5 or 4 and then revs back to 1.2 and keeps on doing it until I turn off the AC or manually revs the throttle to stay at 1. Dropping RPM does also occurs when driving at the night with the lights on so I also checked the battery but battery voltage is alright, now the car is not showing check engine or any sign.I went to different mechanics and everyone says that on the idle car is working fine and go for computer testing again.As I am expat and I am having trouble finding good mechanics here I will appreciate if someone knows what to do solve the problem
PS link of video showing dropping rpm of my car is below
https://youtu.be/YuiiSCSpDes
//https://youtu.be/YuiiSCSpDes