Engine Problems – What Are The Most Common Engine Problems

Engine Problems
Engine Problems

The engine is the heart of any functioning vehicle.

Diagnosing engine problems is not always easy and can be even harder to repair.

If you own a car, there are a few common engine problems that every driver runs into sooner or later.

Whether you’ve been on the road just a few years or for decades, everybody needs to meet basic maintenance demands.

If you’re unfamiliar with basic engine repair, the world of engine service can be intimidating and mysterious.

It turns out, there are a few common engine problems that seem to affect engines on a regular basis.

Not all drivers have the ability to diagnose and properly fix whatever engine problems that might come up.

Knowing the signs and symptoms of some of the most common engine problems, can save you time and money.

Not all engine problems are serious and  some can be remedied relatively quickly.

Here’s a look at some of the most common engine problems out there.

Oxygen Sensors

(O2) Oxygen Sensors
(O2) Oxygen Sensors

Oxygen sensors are one of the most important components on a modern vehicle’s engine management system. They are responsible for monitoring the air fuel mixture of the engine. Oxygen sensor readings affect important engine functions such as timing and air fuel mixture.

Over time, with normal use, oxygen sensors can begin to function with a delayed response, and they will eventually fail.

Typical symptoms of a faulty oxygen sensor are;

  • Decreased engine performance
  • Decreased fuel efficiency
  • Rough idle
  • Engine misfires

Usually a faulty oxygen sensor will set off a check engine light, specifying which sensor on what bank has failed.

Replacing an oxygen sensor is an extremely common repair in older cars. Your oxygen sensor is a vital component of your exhaust system which detects unburned oxygen in your exhaust. As your car ages, your oxygen sensor becomes worn, and is often due for replacement after 100,000 to 150,000 kilometers. Also, Early failure can brought about by other failures like blown head gaskets.

Catalytic Converters

Catalytic Converter
Catalytic Converter

The converter is an emissions related component that is mounted in the exhaust pipe. Its purpose is to superheat unburned particles in the exhaust gases that are expelled from the engine. As the engine runs, the catalytic converter warms up to an operating temperature of 500-1200 °F.

At this temperature the particles in the ‘dirty’ exhaust are burned and converted into water vapor and carbon dioxide.


The catalyst inside is nearly always comprised of precious metals such as platinum, rhodium, or palladium. When the catalyst isn’t able to burn off the unburned hydrocarbons in the exhaust, an unpleasant odor can occur. As well as a rough run or misfire may be felt, or the Check Engine light may illuminate.

Catalytic converters are designed to last the entire lifetime of your car. Overlooked repair issues in other components of the exhaust system can cause wear and breakdown to the catalytic converter. Quite often catalytic converters are contaminated by coolant and fail. While aftermarket catalytic converters are a cost-saving option, most owners rely on original manufacturers to receive standardized and trustworthy parts.

Ignition Coils

Ignition Coil
Ignition Coil

Your ignition coil transform low voltage electrical power 12 volts D.C. to high voltage current 50,000 volts D.C. or higher. Your vehicle’s ignition coil sends an electrical signal from the computer to your spark plugs. The spark generated by them ignites the fuel and air mixture in the engine that enables the car to start.

A failing coil can result in a number of problems, such a stalled vehicle, rough idling, or a vehicle failure. So, If an ignition coil is not working properly, no spark will ignite the air fuel mixture, causing a misfire. A bad ignition coil can severely damage the engine or catalytic converter. If your car is equipped with “coil over plugs,” then it is recommended that you replace the spark plugs.


Spark Plugs

Spark Plugs
Spark Plugs

Failing spark plugs can have several distinct signs, which can help you diagnose this problem.
Most often the recommendations for spark plug replacement intervals tend to be overly optimistic.

For example, if you’ve already got 80,000 miles on a set of 100,000-mile plugs, they’re 80 percent worn and beginning to take a toll on engine performance and gas mileage.

Worse yet, after that many miles, spark plugs have a tendency to seize in the cylinder head. Removing a seized plug can be a costly job, especially if the threads in the cylinder head are damaged in the process. On some vehicles, spark plug replacement may be labor intensive and involve removal of the intake plenum.

Fuel Or Gas Caps

Gas Cap
Gas Cap

The fuel filler cap secures the entry to the fuel tank and is usually made of metal or plastic. Most fuel filler caps have threads, which are fixed to the tank pipe with matching threads. A rubber gasket at the top is compressed when the cap is fixed and it stops fuel and fuel vapor leaks. The fuel filler cap also has air vents that allow the air to enter into the tank and maintain pressure. Generally, fuel filler caps are used as a closure for the fuel tank. Most fuel filler caps are sealed by turning them until you hear a clicking sound.

Other caps have locks within them requiring a key to open them. The emission control system monitors the fuel vapors and illuminates an engine light when there is leakage. If the seal is damaged or if the fuel filler cap does not seal the tank properly, the engine light will be illuminated along with the fuel door light.

If this light comes on, check the fuel filler cap and see if it is screwed on properly. Most of the time, the problem may be solved by replacing the defective gasket.

However, cleaning the cap and/or greasing the gasket may also help in a few cases. A loose fuel cap is a frequent and inexpensive cause of a check engine light. A loose fuel cap can change aspects of the fuel tank that can cause low performance within the engine. If your check engine light is on always check your gas cap first.



A thermostat is part of the cooling system that regulates the temperature of the coolant in the engine. The thermostat is a metal valve that has a temperature sensor built in. It can either be open or closed. When the thermostat is closed, it keeps the coolant in the engine. When the engine gets to a predetermined temperature, the thermostat opens allowing coolant to circulate.

The circulation of coolant prevents the engine from overheating. If the thermostat fails to open, the engine will overheat. If the thermostat fails to close, the engine may never reach the optimal operating temperature (~220F). The thermostat opens and closes many times when the car engine is running. It is the most common component in the cooling system to fail, causing the car to overheat.

Mass Air Flow Sensor


The mass airflow sensor (MAF) helps the engine’s computer maintain optimal combustion. Signs of failure include a rough idle and the car running rich. A mass airflow sensor, or MAF for short, is found almost exclusively on fuel injected engines. A MAF is an electronic device that runs between your vehicle’s air box and intake manifold. It measures the amount of air that passes through it, and sends this information to the engine’s computer, or ECU.

As a result, The ECU takes this information and combines it with air intake temperature data to help determine the proper amount of fuel necessary for an optimal combustion. If your vehicle’s MAF sensor is failing, you will notice rough idling and the vehicle running rich. Your Mass Air Flow Sensor (MAF Sensor) determines the amount of air entering your engine for your car’s computer to use when determining the optimal air-to-fuel ratio in your ignition chamber. MAF sensor failure can happen in cars of any age.

EVAP Purge Control Valve And Solenoid

Purge Control Valve
Purge Control Valve

The purge valve is the part of the vehicle Evaporative Emission Control (EVAP) system. The EVAP system prevents fuel vapors in the fuel tank from escaping into the atmosphere. The EVAP system traps fuel vapors from the fuel tank and temporarily stores them in the charcoal canister. When the engine is running under certain conditions, the fuel vapors are purged from the canister and burned inside the engine.

The purge valve precisely controls the amount of fuel vapor that is purged from the charcoal canister. In modern cars, the purge valve is an electrically-operated solenoid, that is controlled by the engine computer. When the engine is off, the purge valve is closed. When the engine is running and fully warmed up, the engine computer gradually opens the purge valve to allow some amount of fuel vapor to be moved from the charcoal canister to be burned in the engine. The purge flow is monitored by a number of sensors.

If the purge flow is less or more than is expected under the conditions, the computer illuminates the “Check Engine” light.

The most common problem with the purge valve is when it sticks or does not close fully. This may cause the “Check Engine” warning light to come on. In some cars, a stuck-open purge valve can cause difficulty starting right after refueling at a gas station: for the first few seconds the engine may run rough and stumble.

Engine Problems-Conclusion

So, Regardless of the vehicle make and model you drive, engine problems are always around the corner. Consequently, Even with proper maintenance like oil change services, problems can still happen.

Regular maintenance might seem pricey, but it’s also critical to keeping your car in good working condition. If you want to get the most use out of your vehicle, be sure to keep up with maintenance.

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