Dear Brothers, I just wanted to share a issue with my Vitz 99 Throttle body, maybe if someone experience the same issue, he might get a faster solution.
Issue:
1- My Car automatic chokes up, during driving and on idle. (It seems like car is always having High RPM)
2-When mechanic tries to lower its RPM using the provided screw on throttle body, the car RPM can increase, but cannot decrease.
3-As my car was automatic, so automatic choke drives the car by itself and i just have to keep braking.
Resolution:
After checking several items and trying to figure out the issue, it was found out that the butterfly of the throttle body which is of metal has been degraded from its round sides, leaving some space for air and mixture even at idle state of the accelerator.
Now either you can change the butterfly ring, or change throttle body. Both will bring back the car to normal state.
This happens usually to older cars.
Images show the real truth. By the way all the sensors were working Ok.Thanks to my mechanic for figuring out.

