What should I do if Fox's idle speed is unstable?

Solution to unstable idle speed of Fox engine: 1. Adjust, repair or replace the throttle position sensor. 2. Clean or replace the idle speed control valve, and basically set the idle speed with a special decoder. 3. Find the leakage point and seal or replace the phase parts. Although most cars now have fault self-diagnosis systems, there will be cases where self-diagnosis systems with fault surfaces display normal codes or codes unrelated to faults. The following are the causes, diagnosis and troubleshooting of unstable idle speed. 1. Idle switch is not closed: Fault analysis, when idle contact is disconnected, ECU determines that the engine is in partial load state. Diagnostic method: Turn on the air conditioner and turn the steering wheel when idling. The engine speed does not increase, which can prove this fault. Troubleshoot, adjust, repair or replace the throttle position sensor. 2. Idle speed control valve (ISC) failure: failure analysis: due to oil pollution and carbon deposition, the idle speed control valve is slow or stuck, and the throttle valve is poorly closed. The ECU can't adjust the idle speed of the engine correctly, resulting in unstable idle speed. Diagnostic method: Check the starting sound of the idle control valve. If there is no starting sound, the idle control valve is faulty. Troubleshoot, clean or replace the idle speed control valve, and basically set the idle speed with a special decoder. 3. Air leakage in the intake pipe: The fault analysis shows that the opening of the idle control valve increases, and the air intake increases accordingly. When the intake pipe leaks, the intake air volume and the opening of the idle control valve will not strictly follow the original functional relationship, that is, the intake air volume suddenly changes with the change of the idle control valve, and the air flowmeter cannot measure the real intake air volume, which leads to the inaccurate control of the intake air volume by ECU and the unstable idle speed of the engine. Diagnosis method: If you hear the smell of air leakage in the intake pipe, it proves that the air intake system is leaking. Troubleshooting, finding leakage, resealing or replacing phase parts.