- A faulty throttle body can cause high idling and rough running. Inspect it for any damage or carbon build-up. Clean the throttle body and its sensors if needed.
2. Inspect Vacuum Hoses:
- Check all vacuum hoses for cracks, leaks, or loose connections. Any issues can cause rough running, high idle, and other performance problems.
3. Look for Exhaust Issues:
- A glowing red exhaust indicates an extremely rich fuel mixture or a clogged catalytic converter. Check for any exhaust leaks, blockages, or damage to the catalytic converter.
4. Check Fuel Pressure:
- Insufficient fuel pressure can cause high idling and rough running. Use a fuel pressure gauge to check the fuel pressure and ensure it meets the manufacturer's specifications.
5. Scan for Trouble Codes:
- Since the check engine light is on, connect an OBD-II scanner to the vehicle's diagnostic port and scan for trouble codes. This will provide you with specific diagnostic information.
6. Verify Ignition System:
- Check spark plug wires, ignition coils, and spark plugs. Faulty ignition components can lead to rough running, high idling, and decreased performance.
7. Clean Air Filter:
- A clogged or dirty air filter can cause performance issues, including high idle and rough running. Replace the air filter if it's dirty or clogged.
8. Inspect Oxygen Sensor:
- A faulty oxygen sensor can affect fuel mixture and cause high idle and rough running. Check the oxygen sensor for any damage and replace it if necessary.
9. Check Coolant Temperature Sensor:
- A malfunctioning coolant temperature sensor can provide incorrect readings to the engine control unit (ECU), affecting fuel mixture and causing high idling. Test and replace the sensor if needed.
10. Fuel Injection System Issues:
- Check the fuel injectors for any blockages or issues. Dirty or faulty fuel injectors can cause high idle and rough running.
11. Inspect Exhaust Gas Recirculation (EGR) System:
- A faulty EGR valve or carbon build-up in the EGR system can cause high idle and rough running. Check and clean the EGR system if necessary.
12. Engine Mechanical Issues:
- If all other components check out, consider the possibility of engine mechanical issues, such as worn piston rings, valve problems, or cylinder head issues. These require further engine diagnosis by a qualified mechanic.
Remember, diagnosing a high idle and rough running issue can be complex, and it's best to consult a certified mechanic if you are unsure or lack the necessary tools and knowledge.
