Diagnose fuel, ignition, and emissions

The lawn mower sound is typically due to a crack in the combustion system. A vehicle's combustion system features many components, such as cylinders, spark plugs, and exhaust, which are all susceptible to damage. These are the most common issues involving these parts:

• A crack in the exhaust system: The exhaust system serves as a sort of "straw" that throws engine gases to the outside. When the exhaust cracks, it affects the flow of gases, making weird lawn mower sounds.
• Faulty head gaskets: The head gasket is a sealing component inside the engine that prevents fluid and gases from the engine's cylinders from mixing up. However, when this sealing fails, it can allow leaks; the leak can lead to fluid building up on hot surfaces and produce gurgly lawn-mower-like noises when the vehicle is running.
• Faulty spark plugs: Spark plugs are engine components that create a spark; the spark they create ignites the fuel in the combustion process and makes the car start. However, when spark plugs become faulty, like when they are malpositioned or overheating, they fail at "sparking" and produce noisy detonation, resembling a lawn mower sound.
• Engine misfire: An engine misfire happens when there's an issue in the combustion process. Cylinders work with spark plugs and perform controlled explosions in the combustion process, but when a spark plug is faulty, a cylinder might do this explosion wrongfully; this is called a "misfire," and it sounds like a lawn mower.
• Faulty wheel bearing: Wheel bearings are components that help support the weight of the car and provide balance; they're found between the wheels and a large metal rod below the vehicle called an axle. However, as a wheel bearing wears out, it'll cause more rolling friction, generating a lawn mower sound.
• Exhaust manifold leaks: The exhaust manifold is a component inside the engine that collects the resulting gas from cylinders and leads them outside through the exhaust pipe. However, if there's a leak in this system, the exhaust manifold changes the tone of the exhaust gases, producing a lawn mower noise.