The problem is not with the car or it's engine. It's very strange that no one knows this about all Toyota Vitz with 1KR-FE engine is that this particular engine requires a fuel with RON 95 or higher. The only fuel type currently available in Pakistan with RON 95 & above is high octane. That is why there is an Owner's Manual in every car so you take some time and read it. Look below at the attached image from Toyota Vitz Owner's manual.
Weird as it may be, High Octane fuels (95 RON or higher) are generally only recommended for high performance engines and sports utility vehicles only by most manufacturers. I too was very surprised when I discovered that 1KR-FE engine requires High Octane. Considering how expensive High Octane is in Pakistan now, using it in a Vitz totally defeats the purpose of why people buy this car in the first place,The Fuel Economy.
Stop wasting your time on Idle Reset procedures & going through the whole ordeal of throttle body service etc. The car is fine. You are all using the wrong fuel type.
Hope it helps. Uploading...
