What Causes Engine Shaking When Cold?
2 Answers
Engine shaking during cold starts occurs due to incomplete combustion in the cylinders, resulting in insufficient vehicle power output, which leads to vibration. Below are additional details: 1. Before each engine start, keep the ignition key turned for about 3 seconds to allow the PP electronic throttle to perform adaptive learning while enabling the fuel system to build up oil pressure before engine ignition. This practice not only facilitates smoother engine starts but also reduces occurrences of EPC light illumination and idle shaking caused by a dirty throttle. 2. The coolant temperature sensor is one of the critical parameters for the ECU to determine engine operating conditions. If the engine cold-starts at -10°C but the sensor reports "20°C" to the ECU, the system will inject fuel based on 20°C conditions, leading to lean mixture and inevitable shaking.
Well, I've been driving for almost twenty years and have seen plenty of cases of cold engine shaking. The main reason is excessive carbon buildup in the engine, especially on the valves and pistons, which causes uneven combustion during cold starts. Also, aging spark plugs or faulty ignition coils can lead to unstable current flow, resulting in shaking. When the engine is cold, the oil is thicker and less effective at lubrication, which puts extra strain on the engine. One winter, my car shook like a sieve when cold, and after checking everything, replacing the spark plugs made a big difference. I recommend regular engine cleaning and using high-quality motor oil. If the shaking happens frequently, get the fuel system and ignition components checked right away—don’t let it turn into a bigger issue. Safety is no small matter.
