1. Check for Vacuum Leaks:
- Inspect all vacuum hoses and connections for cracks or loose fittings.
- Fix or replace any damaged vacuum hoses or connections.
2. Check Engine Mounts:
- Inspect engine mounts for signs of wear or damage.
- Replace faulty engine mounts if necessary.
3. Clean Throttle Body:
- Remove and clean the throttle body.
- Follow your vehicle's specific instructions for cleaning the throttle body.
4. Fuel System:
- Check for clogged injectors or fuel filter issues.
- Clean or replace fuel injectors/filter if necessary.
- Check fuel pressure and make sure it's within specifications.
5. Ignition System:
- Inspect spark plugs for signs of wear, damage, or incorrect gapping.
- Replace old spark plugs with new ones.
- Check the spark plug wires and distributor cap/rotor (if applicable) for damage.
6. Faulty Sensors:
- Diagnose potential issues with sensors like the oxygen sensor, mass airflow (MAF) sensor, and throttle position (TP) sensor.
- Replace faulty sensors if necessary.
7. Engine Compression:
- Perform a compression test on each cylinder to ensure uniform compression.
- If compression is low in one or more cylinders, further diagnosis is needed (e.g., worn piston rings, leaking valves).
8. Faulty Fuel Injectors:
- Test fuel injector operation to see if any are not functioning properly.
- Replace faulty fuel injectors if necessary.
9. Check Engine Timing:
- Make sure the ignition timing is set correctly as per your vehicle's specifications.
- Adjust the timing if necessary.
10. Computer Diagnosis:
- If the above checks don't resolve the issue, there may be an underlying electrical or electronic problem.
- Connect a diagnostic scanner to the vehicle's OBD-II port and check for any error codes that could indicate specific problems.
11. Professional Diagnosis:
- If you're unable to identify or fix the problem, it's best to consult with a qualified mechanic for a professional diagnosis and repairs.
Remember that shaking at idle can be caused by various factors; thus, it's important to systematically check and troubleshoot the potential issues to find the root cause and fix it effectively.
