What Causes the Automatic Transmission Vehicle to Jerk and Shake During Start-Up?
2 Answers
Here are the specific reasons why an automatic transmission vehicle jerks and shakes during start-up: 1. Faulty Spark Plugs: Failed spark plugs can cause one or more cylinders to misfire, resulting in uneven power output and severe vehicle shaking. 2. Poor Coordination Between Throttle and Clutch: If the clutch is released too quickly, the vehicle may exhibit jerking movements. 3. Fuel Pump Malfunction: When the fuel pump fails, fuel injection becomes uneven. Fluctuating fuel injection amounts lead to inconsistent power output. 4. Cold Start: Insufficient fuel combustion reduces the vehicle's power. During a cold start, when fuel and lubricant temperatures are low, more throttle input is required to meet power demands. Over time, the spark plug gap widens, decreasing ignition energy and causing poor fuel atomization, which results in vehicle shaking.
I think your automatic transmission car jerks when starting, most likely due to worn or aged clutch plates in the transmission. Having driven for many years, I've found that if the clutch is used for too long and the friction material is nearly worn out, it will slip and vibrate during starting and shifting, naturally causing the car body to shake. Another possibility is an issue with the engine ignition system, such as eroded spark plugs failing to ignite properly, leading to uneven power output and sudden jerks when accelerating. You should immediately check if the transmission oil pressure is too low or if there are impurities in the oil that haven't been filtered. I recommend first checking the dipstick—if the oil is too dark or low, it needs to be replaced. This kind of jerking is even more dangerous on highways, as it can easily cause loss of control and collisions when starting. Don't wait until an accident happens to fix it. It's best to have a professional shop inspect the entire drivetrain system.
