Symptoms of Bad Air-Fuel Ratio Sensor

The air-fuel ratio sensor is one of the areas where many people have little knowledge. It is this small equipment that facilitates the smooth running of your engine. It is necessary to make you understand the air-fuel ratio sensor and some of the symptoms that are not functioning correctly. In this guide, we will cover some of the symptoms of bad air-fuel ratio sensor and how to go about it.

What is the Air-Fuel Ratio Sensor

Air-fuel ratio sensor is a device located right inside the engine of your truck. Its primary role is to measure the amount of oxygen in the exhaust gas and pass the information to your truck’s ECU. The air-fuel ratio sensor is necessary for maintaining the health of your engine. For the engine to run in optimum condition, it has to have the same air-to-fuel mixture ratio. 

If there is a change in the air or fuel ratio level, the sensor will detect and send the signal to the ECU. The ECU will later interpret the sensor’s signal and deliver the information through the check engine light, which will appear on your dashboard. Once the engine check light appears on your dashboard, you must take your truck for a mechanical check-up. 

Symptoms of Bad Air-Fuel Ratio Sensor

Rough Idling

Rough idling is a situation in which your truck goes up in RPM, sputters, and then goes back to normal. You will feel rough idling on the floorboard of your truck when the gears are not engaged, and the engine is on.

Rough idling is uncomfortable, and you will feel your truck rumbling. Whenever this happens, think of doing air-fuel ratio sensor checks. 

A Pinging Engine

When your engine pings, you feel a metallic or rattling sound whenever you accelerate from zero to some miles per hour. The rattling sound signals a bad air-fuel ratio sensor. When the combustion cycle is incomplete, then your engine will ping.

Incomplete combustion occurs when there is more or less air in the combustion chamber. The result of incomplete combustion is the release of toxic gases into the atmosphere. 

Poor Fuel Economy

Most truck owners pay attention to how their trucks consume gas. If your truck consumes more, you will spend more money to quench its thirst. Poor fuel economy is a sign that there is a problem with the air-fuel ratio sensor. This sensor detects if the air and fuel getting into the combustion are inadequate or less adequate. 

Too Much Exhaust Fumes Emissions

If you note a lot of fumes when starting your truck, the production of pungent exhaust fumes or your truck generally produces more fumes than usual. All these are indications that the air-fuel ratio sensor is not functioning perfectly. In such a scenario, take your truck for a mechanical check-up to determine the cause is your air-fuel ratio sensor. 


Modern trucks have several sensors in their engine. They play the role of gathering and relaying information to the ECU. The air-fuel ratio sensor monitors the quantity of oxygen available in the exhaust gases. If this sensor malfunctions, your truck might develop mechanical problems. If you notice these signs, seek a mechanical check-up.