Possible causes and solutions:
1. Faulty throttle position sensor:
* Check the throttle position sensor to ensure it is properly calibrated and is sending the required airflow to the engine.
* Replace the faulty throttle position sensor.
2. Problems with the vacuum pump:
* Vacuum leaks or a faulty vacuum pump can cause the engine idle to drop when the brakes are applied.
* Check the vacuum system for leaks or malfunctions.
* Replace the faulty vacuum pump.
3. Clogged injectors:
* Clogged injectors can disrupt the fuel supply, which leads to a lean mixture and a drop in speed.
* Clean or replace clogged injectors.
4. Faulty fuel pressure regulator:
*A faulty fuel pressure regulator can result in incorrect fuel pressure, which affects engine speed.
* Check the fuel pressure regulator and replace it if it is faulty.
5. Faulty Vehicle Speed Sensor (VSS):
*A faulty VSS can send incorrect signals to the transmission, causing the engine to rev or stall.
* Check and replace faulty VSS.
6. Problems with the electronic control system (ECS):
* The ECU may contain faults or incorrect settings, resulting in problems with engine idle speed.
*Consult an experienced mechanic to diagnose and repair ESU problems.
7. Faulty crankshaft or camshaft position sensor:
* A faulty crankshaft or camshaft position sensor can cause the ECU to not know when to spark or inject fuel, causing the engine to stall.
* Check and replace the faulty sensor.