What Causes Engine Shaking After Adding Fuel Additives?

[Terry]

Here are the specific reasons for engine shaking after adding fuel additives: 1. Engine carbon deposits: Excessive dirt on the throttle valve or carbon buildup on the fuel injectors. When there is too much carbon deposit inside the engine, the gasoline sprayed by the cold-start injector will be largely absorbed by the carbon deposits, resulting in an overly lean air-fuel mixture during cold starts, making ignition difficult. In this situation, the engine will only start easily after the carbon deposits have absorbed enough gasoline. After ignition, the gasoline adsorbed on the carbon deposits will be sucked into the combustion chamber by the engine's vacuum, making the air-fuel mixture too rich. The constantly fluctuating air-fuel mixture leads to idle shaking after a cold start. 2. Ignition system malfunction: Check the condition of the spark plugs, high-voltage wires, and ignition coils. Poor performance of the ignition system or inadequate spark plug firing can cause such issues. 3. Unstable fuel pressure: If you have already cleaned the engine carbon deposits, throttle valve, replaced the oil gasket and spark plugs, but still experience body shaking at idle, it is necessary to visit a 4S shop to check the fuel supply pressure and the intake pressure sensor. Abnormal fuel pump pressure or incorrect readings and poor performance of the intake pressure sensor can all cause body shaking.