Skip Navigation

Select Language

Diagnostic Center

My car is hard to start and has no acceleration: could it be the spark plugs?


When you press your vehicle’s accelerator you expect your car to go. When your car starts roughly, hesitates or doesn’t get up to speed in a timely manner, it’s a problem that can leave you stuck in your driveway or on the side of the road.


Once you have determined that you have plenty of gas in your tank, it’s time to start going down the list of problems that can cause your engine to have trouble starting, hesitate or have poor acceleration. At the top of the list is an issue with your vehicle’s spark plugs.

Spark plugs are key to making your vehicle operate. They supply the spark that ignites the air and fuel after they have been mixed together. Without that spark, your car’s engine can’t do what it was designed to do – run efficiently and take you and your family where you want to go.




Rough starts, hesitation and poor acceleration are all common symptoms of a bad spark plug. If a spark plug or multiple spark plugs are faulty, they will have trouble creating the spark that causes the ignition process in your vehicle. This results in your vehicle having trouble starting, hesitating or having issues with accelerating properly.


Over time, residue from the burning air/fuel mixture can form deposits that buildup on the spark plug’s center and side electrodes. This changes the gap of the spark plugs and in some cases can short-circuit the electricity before it reaches the center electrode tip, thus weakening the spark. The weakened spark produces poor combustion which can lead to performance issues including poor acceleration, hesitation and rough starts.


Keeping tabs on how your car is running can give you clues regarding the performance of your spark plugs. If you notice a decrease in your vehicle’s gas mileage and/or a drop in engine performance, it may mean that your spark plugs are worn or dirty. Pinging or knocking noises when accelerating is another sign that your vehicle is due for a spark plug change.



If you suspect that you have an issue with your vehicle’s spark plugs you should either have it inspected by your favorite mechanic or if you are comfortable working on your car, you can examine the spark plugs yourself.


Please note that you should never touch a spark plug or try to remove a plug wire when the engine is running or when it is hot. Before doing any spark plug work on your vehicle, be sure that you understand what the job entails. Learn how to remove and install spark plugs and discover how to read spark plugs.

Learn more about vehicle maintenance products, find your part, or find where to buy your part today.

The content contained in this article is for informational purposes only and should not be used in lieu of seeking professional advice from a certified technician or mechanic. We encourage you to consult with a certified technician or mechanic if you have specific questions or concerns relating to any of the topics covered herein. Under no circumstances will we be liable for any loss or damage caused by your reliance on any content.

Related Stories

Related Parts

Champion® offers a wide variety of products for all your automotive needs.
Check them out!