What Causes the Car to Shake When Warm but Not When Cold?
2 Answers
There are several reasons why a car may shake when warm but not when cold: 1. Unstable fuel pressure: If you have already cleaned the engine carbon deposits, washed the throttle body, replaced the gaskets and spark plugs, but still notice the car shaking at idle, it is recommended to visit a 4S shop to check the fuel supply pressure and the intake pressure sensor. Abnormal fuel pump pressure or incorrect readings and poor performance of the intake pressure sensor can both cause the car to shake. The solution is to check the fuel pressure and replace the components if necessary. 2. Aging engine components: Worn engine mounts can also cause the car to shake. Engine mounts are essentially the shock absorption system of the engine, responsible for absorbing minor vibrations during operation. If the engine mounts are faulty, these vibrations can be transmitted to the steering wheel and the interior of the car.
I've experienced this issue where the car shakes only when it's warmed up. The engine runs fine when cold but starts trembling once it gets hot, usually due to ignition system problems. Spark plugs can expand when hot, increasing the gap and causing misfires, or the fuel injectors might be clogged, leading to uneven air-fuel mixture. From my repair experience, the most common causes are faulty coolant temperature sensors or oxygen sensors sending incorrect data when the engine is warm, resulting in unstable idle. Another issue is excessive carbon buildup in the intake system, making it harder to draw air into the cylinders for combustion when hot. I recommend first checking for loose or aged spark plug and sensor wiring – don't underestimate this as it affects driving smoothness and needs prompt attention. For proper diagnosis, it's best to have a professional shop read the trouble codes when necessary.
