Your engine can fail or misfire when the fuel-air ratio is too rich, leading to engine flooding and spark plug contamination. This can cause misfiring or starting problems. If you experience a rough idle or a reluctant start, the air filter should be the first thing you check. Engine misfires, rough idling, and hard starts can all be attributed to a clogged engine air filter. A blocked air filter restricts the amount of air that reaches the engine, resulting in unburned fuel forming a soot residue that accumulates in the spark plug.
This fouls the spark plug(s) and decreases its ability to produce the spark needed for combustion. Replacing the affected air filter and spark plugs will restore your engine's performance. For an engine to generate power, it needs an adequate amount of air to mix with the fuel for combustion. When a dirty air filter restricts air flow to the engine, it reduces power output. This is especially noticeable during strong acceleration, as the engine requires an increasing amount of air flow to power the cylinders as their rpm increases.
With a blocked air filter, the engine may feel shaky under acceleration, particularly in the upper rpm range. In extreme cases, the engine may not be able to accelerate beyond a certain speed or rpm due to insufficient airflow. The engine needs air, spark and fuel to run. However, if the air cleaner is clogged and dirty, it will literally suffocate the engine, impairing fuel economy and acceleration. Fortunately, this is easy to fix - simply take out the old air filter from the air box, inspect it and replace it with a new one. Most vehicles also have a cabin air filter that is used to clean the air entering the interior of the car, but it has a different maintenance program than an engine air filter.
Refer to your vehicle's owner's manual for the suggested maintenance schedule and replacement procedure for the air cleaner. Older vehicles with carbureted engines will experience a significant drop in fuel economy when their air filters are blocked. If you don't replace them at suggested intervals, you may notice distinctive signs that they need replacing. If you start hearing coughing or clicking noises coming from the engine compartment, or if your vehicle vibrates excessively, it could be a symptom of a dirty air filter damaging a spark plug. The longer you allow dirt to pass through an unclean air filter, the more likely it is that your spark plugs will fail and cause faulty ignition problems. The cabin air cleaner and the engine air cleaner essentially do the same thing, but the engine air cleaner is a line of defense against dirt, dust, and other objects that might otherwise enter and clog up your engine.
The owner's manual should tell you what size your original air filter was so you know which one to order when it's time to change it. This means that you can often save labor costs by replacing your own air filter if you know where it is. If you see black smoke coming from your exhaust pipe, ask your mechanic to replace or clean your air filter. Therefore, cleaning your air filter in newer cars should not significantly affect fuel economy. There are not too many things that cause air filters to fail unexpectedly since they are simple devices with no active movement or mechanical/electronic components and are usually protected by an air box. Many modern engines draw around 10,000 gallons of air for every gallon of fuel burned in their combustion cycle.
These small nozzles deliver a spray of fuel into each cylinder where it mixes with air for compression and combustion. Other symptoms consistent with a faulty air filter will also occur if your engine check light illuminates and an unclean air filter is at fault.
