What is the reason for engine shaking when hot but not when cold?

[SanNova]

The reasons for engine shaking when hot but not when cold are: 1. The idle speed motor is damaged and cannot adjust the opening of the air valve; 2. The fuel injector is clogged or the fuel pump is faulty, causing poor fuel flow; throttle body malfunction, with air leaks preventing proper control of air intake; 3. Faulty intake sensor leading to inability to control air intake; 4. Engine control logic error, making it unable to stabilize idle speed. The solutions for engine shaking when hot but not when cold are: 1. Clean the fuel system and check if the idle speed motor has carbon buildup that needs cleaning; 2. Check if the spark plugs have excessive carbon buildup and replace them if necessary; 3. Check fuel pressure and replace components if needed.