Car Won’t Accelerate Past 60 MPH (11 Common Reasons)

It can be quite annoying when you step on the gas pedal, but your car refuses to go beyond 60 mph. At first, it may seem like a small issue until it happens a couple of times, and you get alarmed.

There are many reasons why this can happen.

Here are some possible reasons why your car will not go past 60 mph.

Check also: Car won’t accelerate at high speeds.

60-miles-per-hour

The ECU Has Activated the Limp Mode

A limp mode is a security feature in cars that activates when the transmission control or engine picks up a fault with your vehicle.

This may even cause your car to not go faster than 20-30 MPH.

Once the issue is detected, the limp mode will cause certain car parts to shut down, and the speed of the car will be affected.

The limp mode lets you know that there is something wrong with your car, giving you time to get home, to a mechanic, or move away from the road.

Several things can trigger this feature.

But once the car computer immediately detects something wrong with the car, it will revert to limp mode to avoid causing further damage. That is why you may be trying to accelerate past 60 mph, but your car will not bulge.

Some of the issues that can trigger a limp mode include:

  • Faulty engine sensors
  • Faulty wiring
  • Transmission issues
  • Low fluid levels
  • Dysfunctional brakes

The best way to fix a limp mode is to take the car to a mechanic.

A professional will inspect your car and solve whatever issue triggered the limp mode.

If you cannot drive to an auto repair shop or are too far from them, call them to come and get you. It is not advisable to drive your car for a long period once the limp mode has been activated.

Dirty or Clogged Fuel Filter

Another reason your car will not accelerate past 60 mph is if the fuel filter is clogged or dirty.

The fuel filter prevents dirt, scale, rust, and other impurities from getting to the fuel pump and engine, and causing damage.

But with time, all those impurities it has been filtering can clog it.

That means the engine will not receive enough fuel, hence affecting acceleration.

Besides poor acceleration, other signs of a dirty fuel filter include:

  • Strong odor from the exhaust pipe
  • The engine does not perform as well as it used to
  • Frequent idling and sputtering
  • Issues starting the engine
  • Engine misfires

Have the fuel filter replaced if your car has been giving you any of these signs.

Dirty or Clogged Air Filters

In the same way, the fuel filter ensures the engine receives clean fuel, the air filter ensures the engine gets clean air to be used in the combustion chambers. But with time, the air filter will get dirty or clogged after filtering impurities of all kinds.

This prevents the engine from getting the right amount of air-fuel mixture, affecting the vehicle’s acceleration.

When the air filter is clogged, the car will give you certain signs like:

  • Strange engine noises
  • Engine misfires
  • Check engine light comes on
  • Black smoke coming from the exhaust pipe
  • Strong fuel smell

You ought to inspect the air filter once a year and see if it needs to be changed.

But most mechanics suggest changing it every 15000 to 30,000 miles for maximum car performance.

Problems With the Timing Belt

When it comes to major components in an engine, the timing belt is one of them.

And if it is off or misaligned by just one tooth, it will lead to a reduction of power, hence affecting acceleration.

Note that besides misalignment issues, a worn-out timing belt will also not function properly, hence affecting acceleration.

To inspect the belt, check on the outer part and see if tiny cracks are forming. One or two cracks are nothing to be alarmed about, but multiple cracks on the surface are a sign that you need a new timing belt.

Many times, a faulty timing belt can also cause the car to not accelerate well during turns.

Faulty Mass Air Flow Sensor (MAS)

The mass air flow sensor determines the air mass entering the fuel injection and passes that information to the ECU.

That information is important as it ensures the right amount of fuel is delivered to the engine.

But when it is faulty, it can send the wrong data to the engine, which will affect your acceleration.

Certain signs that the MAS is faulty include:

  • Check if the engine lights come on
  • Abnormal jolts of power
  • Lean idling
  • Poor fuel economy
  • Black smoke coming from the exhaust pipe

Faulty Throttle Position Sensor (TPS)

The TPS works by detecting the throttle valve opening angle, which is usually controlled by the accelerator pedal.

The TPS then sends this data to the car’s ECU.

If the TPS is faulty, it means that the accelerator pedal will not be able to control the engine speed. Whenever you try accelerating the car under such conditions, the car will not reach higher speeds.

Faulty Oxygen Sensor

The role of the oxygen sensor is to monitor the emissions of the car so that it can assess the air-fuel ratio passing through the engine.

As you are already aware, your car needs the right amount of fuel so that the fuel burns correctly in the combustion cylinders, resulting in the car running smoothly and accelerating as needed.

This sensor sends information to the engine computer unit about the amount of fuel being used.

But when it is damaged, the engine will not have a clue about the air-fuel ratio, which can lead to a rich fuel mixture.

This can cause the vehicle to not accelerate past 60 mph even when pressing the pedal as hard as possible.

Other signs that a vehicle with a faulty oxygen sensor will display include:

  • Poor fuel economy
  • The engine sounds rough
  • Black smoke coming from the exhaust pipe
  • Check if the engine lights come on
  • A bad odor resembling sulfur or rotten eggs coming from the exhaust

Problems With the Clutch

Modern vehicles come with an advanced clutch system that can last more than 100,000 miles.

However, rough driving conditions will damage the clutch and, in return, affect acceleration.

A damaged clutch will slip, especially if you are carrying heavy loads or driving uphill. You will notice that engine speed is increasing, but the car is not going any faster no matter how much you press the gas pedal.

Unfortunately, a slipping clutch can overheat other components, leading to damage.

Clutch slippage is a sign that the clutch is about to fail. Various things can cause this, such as the plate or disc starting to wear out.

Note that if you are an aggressive driver who revs the engines often, your clutch is likely to have issues prematurely.

Check also: Car won’t downshift during acceleration.

Leaks in Vacuum Hoses

Your engine has many vacuum hoses. Their role is to transport air and fuel to and from the engine and other points.

This might cause your car to not accelerate past 4000 RPM.

But when the hose has holes, your engine will not get the right air-fuel ratio. This leads to a lean mixture that will reduce engine power and lead to acceleration issues, such as your car not going beyond 60 mph.

The first sign that you have a vacuum leak is if your idle is higher than normal. The check engine light will also come on, and the engine will either underperform or misfire.

You may also hear vacuum sounds coming from the engine. Park your car in a safe place and listen for sucking, hissing, or squealing sounds. All these can indicate that you have a vacuum leak.

In many instances, the leak results from a broken or cracked hose, which will not cost you a lot. But if the leaks are caused by a serious issue such as a cracked intake manifold, fixing the issue can cost you about $1000.

Clogged or Dirty Fuel Injector

A fuel injector is designed to supply a specific amount of fuel to the combustion chamber. But if it is clogged, there will be poor fuel flow, leading to reduced engine performance and hence issues when you try accelerating.

Fortunately, if you know your way around an engine, you can clean the fuel injector at home. Get a fuel injector kit from an auto store or online.

Most cleaning kits can clean any type of vehicle. But to be safe, read the package carefully and ask the store clerk if the cleaning kit is right for your car.

If your car still has acceleration issues after cleaning, consult a mechanic who will pinpoint the exact problem and fix it.

Faulty Catalytic Converter

The role of a catalytic converter is to ensure that the exhaust gases leave the engine. But when it is faulty, it can cause gases to be trapped in the engine.

This creates a lot of pressure that can lead to the engine losing power.

When this happens, your car can refuse to accelerate past 60 mph because the engine performance has been affected.

Final Thoughts

These are just some of the issues that can cause your car not to accelerate past 60mph.

If you are uncertain about troubleshooting acceleration issues on your own, we recommend going to a mechanic who will diagnose it and suggest the right solution.

Resources

https://cartreatments.com/limp-mode/

https://www.familyhandyman.com/article/car-not-accelerating/

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