I have a 2004 SE Saloon automatic with 1,20,000 KM done. It has devloped a fault that if i increase engine rpm to 2000 or above, then if i release the accelerator suddenly, RPM drops to almost zero.Sometimes even the engine stalls & sometimes doesnt. No engine warning light turns on. Starting & idling of the car is perfect but the problem is occuring once accelerator is released from high RPM.I took it to toyota capital motors islamabad. They connected the OBDII but couldnt find anything. They changed plugs (K16RU-11), air filter, flushed fuel tank, changed fuel filter, changed fuel pump, cleaned throttle body but same fault still exist and they are unable to trace it. Toyota capital says that they wont b able to find the fault unless the ECU gives some trouble code.
I m thinking to replace throttle body and crank shaft position sensor one by one since one of them is culprit as far as i think.
Can any expert help me out???