* Dirty or Faulty Throttle Body: The throttle body controls the air intake. Buildup of dirt, grime, or carbon deposits can restrict airflow, causing erratic idling and shaking. A faulty throttle position sensor (TPS) within the throttle body can also send incorrect signals to the engine control unit (ECU), leading to similar symptoms.
* Vacuum Leaks: A vacuum leak in the intake system can disrupt the air-fuel mixture, resulting in rough idling and RPM fluctuations. Leaks can be anywhere from small cracks in hoses to loose connections.
* Spark Plug Issues: Worn-out, misfiring, or improperly gapped spark plugs can cause a misfire, leading to shaking and inconsistent RPM.
* Ignition Coil Problems: A faulty ignition coil can fail to deliver sufficient spark to one or more cylinders, resulting in a misfire and the symptoms you describe.
* Mass Airflow Sensor (MAF) Problems: The MAF sensor measures the amount of air entering the engine. A dirty or faulty MAF sensor provides inaccurate readings to the ECU, causing poor fuel mixture and erratic idling.
* Engine Mounts: Worn-out engine mounts allow excessive engine movement, which can manifest as shaking, especially at idle.
* Low Engine Compression: If one or more cylinders have low compression, the engine will struggle to run smoothly, resulting in shaking and fluctuating RPMs.
* Faulty PCV Valve (Positive Crankcase Ventilation): A clogged PCV valve can cause excessive crankcase pressure, affecting the engine's performance and leading to rough idling.
What to do:
It's highly recommended you don't attempt major repairs yourself unless you have significant mechanical experience. Improper repairs can worsen the problem.
1. Check Engine Light: If the check engine light is on, get the diagnostic trouble codes (DTCs) scanned at an auto parts store (often free) or a mechanic. The codes will point to specific potential issues.
2. Visual Inspection: Look for any obvious signs of damage, loose connections, or leaks in the intake system, vacuum hoses, or spark plug wires.
3. Professional Diagnosis: Take your car to a qualified mechanic for a proper diagnosis. They have the tools and expertise to identify the exact cause and perform the necessary repairs.
Ignoring this issue could lead to further damage to your engine. Prompt attention is crucial.
