What Makes a Car Engine Shake?

A car engine shake can be a sign of a number of different problems. Some of the most common causes include:

Misfiring spark plugs

Spark plugs are responsible for igniting the air-fuel mixture in the engine’s cylinders. When a spark plug misfires, it can cause the engine to shake because the combustion process is not happening properly. Misfiring spark plugs can be caused by a number of things, including:

Worn or fouled spark plugs
Loose or damaged spark plug wires
Problems with the ignition coil

Vacuum leaks

Vacuum leaks can occur when there is a hole or crack in the intake manifold, carburetor, or other parts of the engine’s intake system. These leaks can cause the engine to shake because they allow unmetered air to enter the engine, which can cause the air-fuel mixture to become too lean. Vacuum leaks can be caused by a number of things, including:

Cracked or loose intake manifold gaskets
Damaged carburetor gaskets
Loose or damaged vacuum hoses

Engine mounts

Engine mounts are responsible for holding the engine in place in the chassis. When an engine mount fails, it can cause the engine to shake because it is no longer able to dampen the vibrations caused by the engine’s operation. Engine mounts can fail due to a number of factors, including:

Wear and tear
Heat
Collision damage

Other causes

In addition to the most common causes listed above, there are a number of other things that can cause a car engine to shake. These include:

Worn or damaged piston rings
Bent or broken valves
Problems with the fuel injector
Problems with the mass airflow sensor

Diagnosis

If your car engine is shaking, it is important to have it diagnosed by a qualified mechanic. The mechanic will be able to determine the cause of the shaking and recommend the appropriate repairs. Some of the diagnostic tests that may be performed include:

Checking the spark plugs
Checking for vacuum leaks
Inspecting the engine mounts

Repair

The repair for a car engine shake will depend on the cause of the problem. In some cases, the repair may be as simple as replacing a spark plug or tightening a loose vacuum hose. In other cases, the repair may be more complex, such as replacing a failed engine mount or repairing a damaged piston ring.