The vast majority of us take for granted that our cars work normally most of the time. We often spend a lot of time in the car, with the average American driving about 13,000 miles per year. It is for these reasons that when things go wrong, we know it almost instantly.
When there are vibrations, noises, rattling, whining, grinding, squeaking and other unsettling sounds, we immediately worry because all of our regular driving helps us know what’s normal and what’s right.
In today’s blog, we’re exploring in particular those times when you are just getting onto the road and starting to open up the throttle. You immediately notice that the car hesitates and jerks when accelerating, but why? This question and others we will try to answer below. If the check engine light is on, it may be more obvious, but here we discuss some more subtle issues.
My Car Hesitates and Jerks When Accelerating – Why?
Problems in acceleration can typically be attributed so issues with the fuel system. It could be that you don’t have enough gas, or there’s a lack of air and/or spark during the engine’s internal combustion process. Alternatively, it could be being caused by a clogged catalytic converter. We’ll look at these explanations and others in more detail below.
The fuel system of a car is a very complex and involved one, with many interconnected parts that rely on each other functioning in order to do their own task. Below are some common fuel-system-related things that tend to result in your car hesitating and jerking as you accelerate:
Fuel Injectors are Dirty
This is arguably the most common cause behind the jerking motion. A dirty injector means that you car loses power and will cause misfires to happen. Very often when people plug in an OBD-II scanner after experiencing that their car hesitates and jerks as they accelerate, they get a code like P0302, which indicates a misfire in one of the cylinders (in this case cylinder 2).
Blockages or Pressure Loss
If there’s anything in the lines that is blocking fuel getting to where it needs to be to mix with air and make that potent spray that powers your engine, then acceleration will be adversely affected. Even partial blockages will reduce pressure to insufficient levels. If there holes in the fuel lines, then you might have something more dangerous on your hands because that can cause engine fires.
Spark Plugs are Worn Out
The spark plugs are there to ignite the fuel in the piston. If they have gone too far past their prime and are now igniting too slowly or not at all, then it could be that replacing the spark plugs will solve this problem. This can be a pretty simple fix and ultimately not take too much longer than a typical oil change. This is often the issue in our experience.
If your car’s carburetor is damaged, then it can’t properly perform the function of managing how much fuel and air are mixed together before entering the engine. If besides the hesitation and jerking when accelerating you also notice other drops in performance for your car, then a damaged carburetor might be the culprit.
Other Potential Problem Areas
Below are some additional problem areas that could be responsible for making your car jerk and hesitate when accelerating.
If you ever find that it manages to lock up your steering wheel, take a look at our guide for fixing that quick and easy!
When was the last time you changed the air filter in your car? This filter plays a vital role in keeping all manner of dust and other contaminants out of the engine. A heavy buildup on the air filter will reduce its efficacy and leave you with a car that is struggling --- perhaps also jerking and hesitating --- as you try to accelerate and get on your way.
Damage to the Cylinders
This is connected to the issue with the fuel injector, but if the problem is with the cylinder instead, the same misfires and jerky driving experience is bound to happen. Once again, an OBD-II scanner not only can confirm that it was a cylinder misfire, but can even tell you specifically which cylinder had the problem.
Blocked Catalytic Converter
A blocked catalytic converter is another common cause of the loss of smoothness of acceleration that you are experiencing, not to mention a host of other potential performance issues. The remedy to this might be the use of an effective catalytic converter cleaner product, which are very easy to use, with off-the-shelf DIY varieties consistently improving in performance.
Damaged Acceleration Cables
The acceleration cable provides the link between your gas cable and the throttle plate. If this cable sustains damage, then it won’t be able to pull the throttle open smoothly, which might be the cause of your problem.
Solutions to When Your Car Hesitates and Jerks as You Accelerate.
Problems in the fuel system can generally be solved with a cleaning and clearing process to remove blockages, open up the injectors properly and prevent those kinds of misfires from happening that are causing the uneven and jerky driving experience. Cleaning should help to ensure that even amount of fuel is distributed that will allow all the processes of combustion to happen as they should.
If cleaning isn’t quite enough, however, then you may have to replace some of the components. The coils in the cylinders, for example, might need to replaced, or you could need to switch out certain components such as the air filter or spark plugs. The good news is that replacing these components is very straightforward and not expensive. If you have a good working knowledge of your car’s engine, then you can easily do it yourself, too.
We touched above on how to deal with a blocked catalytic converter. The first step would be to purchase a good catalytic converter cleaner to see if that clears the blockage. Many of them do and your car will be ticking over nicely. If a cleaning kit doesn’t do the trick but you are still sure (perhaps from an OBD-II scan) that it’s the catalytic converter that is blocked, then a trip to the auto shop is in order.
If you had to replace the carburetor, it wouldn’t be the end of the world and likely at the most would reach $200 for a professional to do it, and likely much less. Having to replace a catalytic converter is a more serious proposition, however, with estimates at $1000-2500. If you know it’s a converter blockage and your cleaning hasn’t worked, you need to get it seen it quickly before it becomes irreparable.
Should I Worry When My Car Jerks or Hesitates During Acceleration?
In short, no. If you have your own OBD-II scan tool, you can quickly determine what is going on, even if you don’t plan to fix it yourself. These scanners can be operated with quite rudimentary knowledge.
In our view, however, the best course of action always remains taking the car to a professional auto shop for them to inspect it, find the cause and get you back on the road. Almost none of the work required to fix the problems takes more than a day, and many could finish on the same day, perhaps even within the hour if they aren’t too busy!