Engine misfires when accelerating? Causes and fixes

What causes the engine to misfire when accelerating?

Some of the most common causes of an engine misfiring while accelerating include worn-out spark plugs, bad spark plug wiring, a cracked distributor cap, a failing throttle position sensor, or dirty fuel injectors.

Therefore, before a vehicle owner or their mechanic can get to the root of this type of problem, they may need to troubleshoot each one before it can be repaired properly.

So, let’s take a quick look at each cause to see if these problems can be identified relatively quickly.

Causes of a misfiring engine when accelerating

1. Engine Backfires Because of Bad Spark Plugs/ Spark Plug Wiring

As mentioned above, one possible cause of a car backfiring while accelerating is a bad spark plug. A bad spark plug may refuse to “spark,” whenever the exhaust valve opens.

Unfortunately, as a result of this type of malfunction, the air/fuel mixture is normally too rich to burn all of the fuel properly. And will more than likely leave excess fuel in the exhaust system.

This is also why the driver may hear a very “loud bang” coming out of the tailpipe. Also, the same actions may occur if the spark plug wiring is too corroded and will not produce a spark.

2. Engine Backfires and Cracked Distributor Cap

A bad distributor cap can also cause the engine in a vehicle to misfire while accelerating. Because one of its primary functions is to generate combustion, a cracked distributor can lead to several unwanted mechanical issues, including a car’s engine hesitating and missing while accelerating.

This is especially the case in cold weather because extremely frigid temperatures may cause the distributor cap to freeze.

3. Engine Backfires and TPS (Throttle Position Sensor)

A malfunction in the throttle position sensor is another common cause of an engine misfiring while accelerating. Since it plays a huge role in regulating how much fuel the engine gets at any point in time, a bad sensor may also result in the engine backfiring.

In some cases, however, these problems may only happen intermittently so it may be a little more difficult for the mechanic to pinpoint.

4. Engine Backfires and Dirty Fuel Injectors

The quality of the car’s fuel injectors may degrade overtime time, and there are many reasons why. One of the most commonly known is often related to the dirt and grime build-up.

Dirty fuel injectors may cause a wide range of malfunctions, from poor gas mileage to car engine misfires.

How much does it cost to fix a misfire when accelerating?

The cost of fixing an engine misfire when accelerating is dependent upon the actual cause of the problem. Therefore, if you do your research, you will find that the cost can vary greatly from one repair job to another. And here are a few examples of the cost.

Cost of New Spark Plugs/ Spark Plug Wiring

To replace bad spark plugs, the cost can range from $16 to $100 for a set of spark plugs.

To replace a bad spark plug wiring, the cost can range from $195 to $242 for a set of spark plugs (excludes labor, which ranges from $67 and $84).

Cost of Replacing a bad distributor cap

To replace a bad distributor cap, the cost can range from $75 to $200.

Cost of Replacing Throttle Position Sensor

To replace a throttle position sensor problem, the cost can range from $157 and $202.

Cost of Dirty Fuel Injectors Servicing

To clean dirty fuel injectors, the cost can range from $50 to $80.

Can an engine misfire fix itself?

No, these types of problems do not fix themselves. However, if an engine misfires, this is an indication that something serious is wrong and needs to be repaired right away.

This is primarily because a minor problem can lead to a very expensive engine repair job.

Can a misfire cause acceleration problems?

Yes, a misfire can lead to several different problems with its acceleration. For instance, you may begin to experience one or more of the following:

  • Jerking motions
  • Sluggish acceleration
  • Car stalls and vibrates

Does driving with a misfire damage my engine?

Yes, if you continue to drive your car without getting the appropriate repairs, more extensive damage can be caused. The longer you wait to address these concerns, it may even lead to catastrophic damage to the engine


There are many different causes of an engine misfire when accelerating. Some of the most commonly known causes include worn-out spark plugs, bad spark plug wiring, a cracked distributor cap, a failing throttle position sensor, or dirty fuel injectors.

Whatever the case or situation, this problem needs to be repaired right away. If not, the damages to the engine may even lead to a very costly problem, including paying for a new engine and labor to install it.

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