How a bad oil pressure sensor can cause rough idle to your car

Let’s face it, many engine problems can be traced back to a faulty oil pressure sensor. One of the most common engine problems is a rough idle that is characterized by some shaking and bouncing movements in the vehicle as the engine runs at idle.

Regarding this sensor, automotive enthusiasts often asked me the following question:

Can a bad oil pressure sensor cause rough idle?

The short answer is YES. After all, the problem can be a result of low oil pressure in the engine. Keep in mind that a faulty oil pressure sensor can cause low oil pressure by affecting the valve lifters causing them to not work properly to ensure that oil is getting to all parts of the engine with the correct pressure.

What Happens When the Oil Pressure Sensor Goes Bad?

Many things can occur when your oil pressure sensor becomes faulty. One of them is that it will affect the valve lifters, preventing them from playing their role effectively, as explained above.

Valve lifters sit between the camshaft and the cylinder valves. A car comes with multiple lifters depending on the number of cylinders the engine has.

There are two valve lifters per cylinder and a typical car has four, six, or eight cylinders. Meaning if your car has four cylinders, six cylinders, or eight cylinders, the engine will have 8, 12, or 16 valve lifters, respectively.

As you already know, the work of a valve lifter is to open and close the valves, using the motion of the cam lobe, which is a component of the camshaft. Oil will reach the internal components of the engine through the open valves in a fairly complex process.

Can Oil Pressure Affect Idle?

The short answer is YES. When the oil pressure is abnormal, it could mean that oil is not reaching all the internal components of the engine as required.

Consequently, this may cause friction between those components that may result in shaking and vibrations movements that are easier to detect when the engine is running at idle.

If your engine is acting up when idling as described above, the first thing you should check is your oil pressure sensor. It could be that the sensor is faulty and therefore unable to perform its function—open and close the valve lifters as necessary.

This can mean low oil pressure and friction in the internal components of your engine, which could be the reasons behind the rough idle.

Unfortunately, many people fail to think about their sensor whenever they are trying to figure out the reason why their engine is idling rough.

Can a Bad Oil Pressure Sensor Cause Reduced Engine Power?

Yes, absolutely. Matter of fact, this is a guaranteed repercussion even though people have mixed opinions. Let me explain to you why a bad oil pressure sensor is more than likely to hurt your engine’s power:

First, the sensor will not be able to perform its function as expected. This will lead to reduced oil pressure in the engine as the valve lifters experience trouble opening and closing the valves so that sufficient lubrication can get into the internal components of your engine.

This will lead to friction and damage to the critical components that your engine derives its power from. One of them is the crankshaft, which is essentially the backbone of your engine.

The engine’s power is measured in horsepower(HP) and one of the well-known factors that can lower or optimize it is the condition of the crankshaft.

If the shaft is unhealthy due to issues like insufficient lubrication, it will reduce your engine’s power. But if it’s healthy and well-maintained with proper lubrication, it will make it easy for the engine to reach its full power without a problem.

Can a Bad Oil Pressure Sensor Cause a Knock?

The normal engine sound can be described as a smooth rumble many people are used to. If the engine is producing a sharp, repetitive pinging or tapping sound instead, that can be described as knocking, especially if it becomes louder as you increase the speed of the car.

The engine will knock mostly when the fuel is burning unevenly or all at once instead of smoothly in small, regulated pockets. Usually, this is caused by an incorrect balance of air-fuel mixture in one or several cylinders.

A bad oil pressure sensor can cause this problem due to its inability to cause the valve lifters to open and close the valves accordingly.

Two types of valves can be found in the internal combustion engine; inlet valves and exhaust valves. The former lets the fuel-air mixture into the combustion chamber when open and the latter expels the burned gasses from the chamber, sending them to the exhaust system.

Now, both valves should open and close systematically, failure of which could see the chamber(s) receive an unbalanced air-fuel mixture, resulting in a knock.

How Much Does It Cost to Replace a Bad Oil Pressure Sensor?

The good news is that a bad oil pressure sensor is fairly inexpensive to fix compared to other engine problems. The average cost of a replacement sensor is about $58, depending on your car model.

Labor costs around $71 and $90, depending on where you may decide to take your car for the repair work besides your car model.

That is to say, you can expect to pay between $58(if you choose to do it alone) and $148($58 + $90) if you choose an expensive mechanic for one reason or another.


The oil pressure sensor is a tiny and inexpensive component of your engine that can lead to different kinds of unexpected problems if faulty.

The cheap component can cause your engine to knock, experience a rough idle, and lose power if it’s bad. In the worst-case scenario, it can kill your engine completely due to friction damage to the critical internal components of your engine e.g the crankshaft. That’s why you should always take any indication of an issue with it very very seriously.

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