Is it normal for the engine to shake at 800 rpm idle but smooth out at 1000 rpm?
2 Answers
This is not a normal situation. Once the engine exhibits such issues, it's necessary to check whether the idle speed motor is malfunctioning. Engine shaking at idle can lead to increased fuel consumption during vehicle operation, unsteady acceleration, and carbon buildup inside the engine. Here's relevant information: Increased carbon deposits should not be allowed with prolonged idling. Keeping the vehicle idling for extended periods will cause more carbon buildup in the engine, resulting in reduced power during driving. The normal idling duration for a vehicle is 3-5 minutes. If it exceeds this time, the vehicle should be turned off. Normal idle speed: The standard idle speed is around 750 rpm. If the engine speed drops below 750 rpm during idling, the vehicle is prone to stalling. If the idle speed is too high, it will increase fuel consumption. You can determine whether the vehicle is operating normally by observing its idle speed value.
I recently experienced a similar issue when driving my friend's SUV. At an idle speed of 800 RPM, the steering wheel noticeably vibrated, and the body shook slightly, which was quite alarming. However, as soon as I lightly pressed the accelerator to reach 1000 RPM, the shaking disappeared completely. This is definitely not normal. I think common causes might include ignition system problems, such as aging spark plugs leaking electricity or poor contact in the ignition coils. Another possibility could be excessive carbon buildup in the engine, affecting combustion efficiency at idle. Dirty fuel injectors causing uneven fuel supply can also lead to this issue. If you frequently idle for long periods while driving, carbon deposits can accumulate faster. If left unaddressed, fuel consumption may increase, and over time, it could lead to internal engine wear. I recommend first checking the spark plugs yourself—they're quite simple to replace. If there's no improvement, then take it to a professional shop to read the fault codes for diagnosis. Don't delay; safety comes first.
