How to diagnose and eliminate poor idle speed of sprinkler?

Cause of unstable idle speed: 1. Failed to turn off the idle switch. Diagnostic method: turn on the air conditioner and turn the steering wheel at idle speed. The engine speed does not increase, which can prove this fault. Troubleshooting: Adjust, repair or replace the throttle position sensor. 2. Idle speed control valve (ISC) fault diagnosis method: Check the action sound of the idle speed control valve. If there is no action sound, the idle speed control valve is faulty. Troubleshooting: Clean or replace the idle speed control valve, and set the idle speed with a special decoder. 3. Diagnosis method of air leakage in the air intake pipe: If you hear the sniffing sound of air leakage in the air intake pipe, it proves that the air intake system is leaking. Troubleshooting: Find the leakage, reseal or replace the phase parts. 4. Diagnostic method of dripping or clogging of the fuel injector: check whether the fuel injector makes a clicking sound or measure the fuel injection quantity of the fuel injector with a stethoscope. If the injector does not click or the injection quantity exceeds the standard, the injector is faulty. Troubleshooting: Clean the injectors and check the fuel injection quantity of each injector to ensure that there is no blockage or leakage.