Why does the engine shake when starting and then stall?
2 Answers
The main reasons for engine shaking are as follows: 1. This is the most common cause of engine shaking, and the problem lies in the engine ignition coil or spark plug. If the ignition coil malfunctions or the spark plug fails to fire for some reason, the car will experience shaking. Misfiring is also a relatively easy fault to diagnose. If the car shakes significantly more than usual during medium to low-speed operation and feels sluggish during acceleration, it can generally be concluded that the engine is misfiring. 2. If severe carbon buildup inside the cylinder causes the engine spark plug or valves to clog, the engine will also experience shaking. If the car's acceleration performance has significantly declined and the shaking is persistent, it may be necessary to consider cleaning the engine cylinder.
I've encountered this situation several times. When the engine starts cold, it shakes violently and then stalls, mostly due to fuel or electrical system issues. Last time my car had this problem, it was caused by excessive carbon buildup on the spark plugs leading to poor ignition, and it was fixed after replacing the spark plugs. Another time, I found that the fuel injector was clogged, preventing proper fuel atomization. A dirty mass air flow sensor can also cause the engine control unit to miscalculate the fuel supply. For older cars, special attention should be paid to insufficient fuel pump pressure—if fuel isn't delivered properly, the engine will naturally stall. If this happens in summer, check if the charcoal canister purge valve is stuck. It's best to connect an OBD scanner to read the fault codes, so you don’t end up replacing three or four parts like I did before finding the real issue. I recommend first checking the ignition coils and spark plugs, and cleaning the throttle body to see if that helps.
