Possible reasons:
1. Faulty throttle position sensor (TPS)
* Monitors the throttle position and communicates this to the ECU to adjust the fuel supply.
*A faulty TPS sensor can cause the ECU to receive incorrect signals, resulting in incorrect fuel adjustments and engine stalling.
2. Faulty crankshaft position (CKP) sensor
* Monitors the position of the crankshaft and reports this to the ECU.
* A faulty CKP may cause the ECU to be unable to synchronize the ignition and fuel delivery, causing the engine to stall.
3. Faulty idle air control (IAC) valve
*Adjusts idle air supply to maintain set engine speed.
*A faulty IAC can cause the engine to idle rough or stall when up to speed.
4. Faulty torque converter
* Connects the engine and transmission.
*A faulty torque converter can cause power transmission problems and stall the engine when up to speed.
5. Low gearbox fluid level
* Provides lubrication and power transmission in the gearbox.
*Low fluid levels can cause increased friction and engine stalling when up to speed.
6. Contaminated fluid in the gearbox
*Over time, the transmission fluid can become contaminated.
* Contaminated fluid may cause gear shifting problems or engine stalling when the vehicle is in gear.
7. Mechanical problem in the gearbox
*These may include worn gears, faulty solenoids, or damaged parts.
*Mechanical problems may cause gear shifting problems or engine stalling when up to speed.
Diagnostics and repair:
1. Scan the vehicle for trouble codes.
2. Check and replace TPS and CKP sensors if necessary.
3. Clean or replace IAC valve.
4. Check the fluid level in the gearbox and, if necessary, top it up.
5. Flush and replace the transmission fluid.
6. Have any mechanical transmission problems diagnosed and repaired by a professional mechanic.