If your "check engine" light has recently come on, it's easy to slip into panic mode. But fortunately, it could be something minor and easy to repair. The best way to know for sure what's going on underneath the warning sign is to take your car to a mechanic; they can use a tool to diagnose the problem on the spot, and you can get it fixed while you're there. But if curiosity has got the better of you, or you want to try to fix it yourself, here are five things that may be going on with your car.

Loose Gas Cap

Most drivers give about as much thought to their gas cap as they do last week's weather. But if something is amiss, your check engine light will often let you know.

The gas cap serves as more than just a cover for your tank. It prevents spillage and evaporation as well as the subsequent release of hydrocarbons into the atmosphere. It also seals the tank, maintaining the right amount of pressure inside to keep the fuel pump working correctly in newer cars. In older cars, leaving the gas cap off can also allow dust and debris to enter the tank, ultimately leading to a clogged fuel filter.

Your car can't really tell if the cap is just loose or if it's missing altogether, which is why the check engine light comes on. So if it's not screwed on tight or it's gone, tightening or replacing it should fix the problem and force that check engine light to turn off.

Tune-Up Needed

Unless you drive a diesel, the spark plugs are responsible for getting that ignition going and starting your car. When they go bad, your car will usually start, but it will also display some of the following behavior:

• Engine surges or misfires
• Engine starts or idles rough
• Car is slow to accelerate
• Gas mileage decreases

If the check engine light brightens up the dashboard and you're experiencing any of the above issues, it could be time for a tune-up to replace those spark plugs and make everything good as new.  

MAF (Mass Air Flow) Sensor Gone Bad

These wonderful sensors are responsible for keeping track of how much air gets to your engine and how much fuel needs to burn as a result. When the sensor begins to fail, it can cause a number of problems, one of which is letting an excess amount of gas run through the engine without all of it being used. This usually manifests as a decrease in gas mileage, but bad MAF sensors can also cause your engine to stall or idle rough.

Catalytic Converter Clogged

Yet another critical component of your vehicle, the catalytic converter changes carbon monoxide to carbon dioxide. It rests between the engine and the muffler, and without this special piece of equipment, your car would not pass an emissions test. A catalytic converter can become clogged, and the warning signs typically include:

• Failing to accelerate when hitting the gas pedal
• Engine shut-off due to back pressure in the exhaust
• A drop in gas mileage

Any one of these occurring in conjunction with the check engine light means it's time to have that catalytic converter checked. 

Oxygen Sensor on the Fritz

If your car was made after 1980, it should have a working oxygen sensor. Overall, it makes sure your engine runs at top-notch performance. But more specifically, it measures the unused oxygen in the exhaust system and from there determines how much gas should be burned.

The oxygen sensor sits in front of the catalytic converter, so they work hand-in-hand to do their jobs. When the sensor goes out or starts to fail, it can pollute the engine and make your car's performance drop all the way around. Replacing this part is pretty simple and can be done by most any auto mechanic. 

To learn more, contact services like Western Avenue Nissan.