Is It Normal for a Cold Engine to Shake While a Warm Engine Runs Smoothly?

[MaddoxAnn]

If the phenomenon of a cold engine shaking while the warm engine runs smoothly occurs during winter vehicle startup, and the shaking is slight—unnoticeable in the driver's seat but observable when the hood is opened—it is considered normal. This happens because, at low temperatures, the idle speed is high after a cold start. The high idle speed leads to increased engine RPM, causing the vehicle to shake. Once the engine warms up and the RPM decreases, the shaking disappears. Causes of cold engine shaking include: 1. Mechanical engine faults, such as uneven cylinder pressure across cylinders; 2. Intake system issues, like intake pipe leaks, excessive carbon buildup on intake valves and pipes, or dirty throttle bodies and intake pipe interiors; 3. Engine management system failures, such as incorrect coolant or intake temperature signals, or wiring faults.