Why is the car shaking violently when starting?

[LaLeah]

Severe shaking during vehicle startup could indicate an engine malfunction. The following are potential faults: 1. Engine mechanical failure: Uneven cylinder pressure across cylinders. 2. Intake system malfunction: Intake pipe leaks, excessive carbon buildup on intake valves and pipes, excessive dirt on throttle body and intake pipe walls. 3. Engine management system failure: Incorrect coolant temperature or intake air temperature signals, wiring faults. 4. Ignition system malfunction: Excessive carbon buildup on spark plugs or incorrect gap, leakage in high-voltage wires or distributor cap, damaged ignition coils. 5. Fuel delivery system failure: Fuel injector sealing issues or clogging due to excessive internal carbon deposits.