What are the reasons for engine shaking during cold start?
3 Answers
Engine shaking during cold start is caused by: 1. Severe engine carbon deposits; 2. Dirty throttle or excessive carbon deposits on fuel injectors; 3. Faulty spark plugs, high-voltage wires, or ignition coils; 4. Unstable oil pressure; 5. Aging engine mounts. Solutions for engine shaking during cold start: 1. Clean the fuel system using an intravenous drip method; 2. Check the carbon deposit condition of the idle speed motor and clean it promptly; 3. Inspect the working condition of spark plugs and replace them in time; 4. Check the fuel supply pressure and the condition of the intake pressure sensor; 5. Examine the electrode gap; 6. Inspect the oxygen sensor; 7. Check the coolant temperature sensor by immersing it in warm water and measuring the change in its resistance value. If there is no change, it indicates damage.
With over a decade of experience in auto repair, I've encountered numerous cold-start shaking issues, primarily caused by engine oil thickening at low temperatures, increasing friction and causing unstable operation. Another common culprit is aged or heavily carbon-fouled spark plugs, leading to misfires and incomplete combustion. Dirty fuel injectors can also impair fuel atomization, making the engine more prone to shaking. A malfunctioning mass airflow sensor disrupts the air-fuel balance, further complicating matters. Carbon buildup inside the cylinders, altering compression ratios, exacerbates the problem. Additionally, don't overlook loose or dry engine mounts, which amplify vibrations. For driving safety, I recommend regular oil changes, spark plug replacements, and carbon cleaning. Preheating the engine for a few minutes before winter starts can help, but if shaking persists severely, promptly visit a professional shop to avoid safety hazards, compromised driving experience, and unnecessary expenses.
After driving for 20 years, I've encountered cold starts shaking like an earthquake, mostly due to engine oil thickening like glue in low temperatures, causing insufficient lubrication and increased internal friction. As the ignition system ages, failed spark plugs or coils can delay ignition and trigger shaking. Carbon buildup in the fuel system clogging the injectors also leads to uneven fuel spray. Dirty air sensors disrupting airflow worsen the situation. Thick carbon deposits cause uneven compression, amplifying vibrations. Loose engine mounts further destabilize the system and magnify the problem. Safety-wise, I always emphasize not to overlook this—early cleaning of fuel injectors or replacing spark plugs can save money and prevent major repairs. Developing a habit of checking oil condition and mount bolts helps avoid unexpected stalling. Keeping the car running smoothly is key to peace of mind.
