If your car is jerking, these may be the main reasons

As a general rule, when you don’t know how something works, it’s a headache if something happens. Especially if that thing is a car, which we drive to work with every day, and how can we expect it, it is a real nuisance to get stuck in the middle of the road.

However, most breakdowns tend to give certain warnings before leaving us stranded on the road. Knowing where they come from and why they come, can make the difference between standing somewhere unsuitable or, conversely, arrive on time at the workshop and everything is solved quickly.

One of the most annoying symptoms and that generates more uncertainty to the drivers, are the typical pulls when we circulate. They are a nuisance, they make driving very uncomfortable and, in addition, they put us under stress by not knowing what is happening. Luckily, it may be very little, but it’s better not to let it go and put it right.

Listening, observing, and diagnosing will give us many of the answers before we even get to the workshop

With the cars we drive today, loaded with technology and for which very specific equipment is required to diagnose the breakdown, the best way to avoid major problems is to go to our trusted workshop as soon as possible. But that doesn’t mean that we can’t do anything on our own to find out what’s wrong and even to fix it.

Having a good diagnosis leads to a better resolution of the fault, so instead of shaking, we can and should do some things. Nobody knows the car better than us and taking into account that when we arrive at the workshop the mechanic will ask us many questions, it is best to listen and observe our car to have the possible answers.

Knowing when and how it happens will help us

Tripping can be due to multiple reasons and the imperious need to know what is happening to the car, it produces a restlessness and discomfort at the time of driving that is not anything advisable for our security nor for those who surround us.

Two possible causes: power supply or electrical problems

We can include the possible causes in two main groups. On the one hand, power problems and on the other hand, unexpected electrical problems. But there are also other sections that can be very important to solve the problem:

  • When does it happen, cold or hot?
  • At what speed or what revolutions does it happen?
  • Does it happen with any type of fuel in particular?
  • When did it start happening?
  • Does it happen when I turn on the air conditioning or other car system?
  • Does it happen when I change gear?
  • Does it happen more when I’m accelerating, or when I’m retaining?
  • Is it associated with any noise?
  • Does it pull when the car is idling?

Knowing how to answer these questions will be very useful when we get to the workshop. This is important information, because as we said before, nobody knows your car better than its owner and can know for example which noises are normal and have always been there and which not. Of course, some warnings can be reflected in our dashboard, but to understand them will need to connect the famous machine, which is nothing more than a computer with an OBD port and a special program.

Intake, exhaust and feed, main sources of pull

The basis for the operation of a combustion engine is that the fuel-air mixture is optimal, combustion is efficient and that after burning, the gases can be expelled easily. To better understand the idea, it is important to know that the feed is the supply of fuel from the tank to the engine and that the breathing, to call it in some way, is focused on the circulation of air to the engine (intake) and the exit of the smoke produced after burning the fuel (exhaust).

For this reason, cleanliness in a circuit, designed to hundredths of a millimeter, is an indispensable requirement. Most of the problems caused by the vehicle’s power supply are due to problems related to the dirt in the circuit. Small particles obstruct the pipes and prevent the efficient circulation of fuel, which does not reach the injection system as it should (carburetion in very old models), causing small pulls. It is also possible that dirty fuel arrives, causing poor combustion.


The feeding system incorporates several filters for the fuel, in order to prevent it from reaching the engine. If those filters are not replaced when it is time (each manufacturer informs about it in their cars’ manuals), it does not allow a free circulation of the fuel or it does, but with dirt. Do not extend their life and change them whenever necessary.

Injectors are usually one of the main sources of pulling, but there are products and additives that can help in their cleaning. They are poured into the fuel tank, next to it and every certain number of kilometers, helping to keep the circuit clean. They are not miracle products and should not be abused, but they help. However, if the tugs are still present, it is best to go to the workshop and a mechanic, with knowledge and experience of many other similar occasions, will be able to find the problem and solve it.

The air filter is an element that many drivers forget about, because its maintenance is really minimal and, as a rule, when we go to the workshop for the relevant periodic revision, it is usually changed for a new one. However, the air filter is another source of stress, since the air that enters from the outside towards the engine, passes yes or no through it. If it is dirty, the air does not circulate normally and the engine lacks oxygen for optimal combustion, which in certain cases causes pulling.

Its revision is not usually complicated, they are in a plastic box with pressure closures, which when removing the lid leaves the filter completely visible, not even needing to be removed. They are usually made of paper, you can see their light and white color when they are new and they can turn almost black when they are very, very dirty. If the air filter does not look like paper, just pull it out and we can go buy another one, which, on the other hand, are really cheap (between 10 and 50 euros, depending on the brand and/or type of filter). Placing it is simple, they have a position and if it is not placed in that position, it does not enter completely into the box and the lid does not close.

Finally, if the burnt gases are not expelled well, this may be due to obstructions in the exhaust system, although this is not the most common. There are other reasons that cause problems in the expulsion of combustion smoke. There are different sensors that can give erroneous readings and cause pulling. In this system, the catalyst plays a very important role, although before pulling, it usually has other problems.

When the fuel is not burned properly, in very, very extreme cases, it ends up reaching the exhaust system and will end up burning when it reaches the catalyst. This will cause excessive overheating to cause even the melting of the ceramic substrate. But this would be a very extreme case because the catalyst is designed to work at temperatures above 700 degrees.

Gas recirculation or EGR

Pulling, coupled with problems in starting, increased fuel consumption, excessive smoke and lack of power among others, are symptoms of failure in the famous EGR valve (Exhaust Gas Recirculation), whose function is to make part of the gases coming out of the exhaust to the intake. That is, it opens a circuit through which some of the combustion smoke is returned to the engine to burn again.

This valve is exposed to very high temperatures, accumulation of dirt by charcoal and oil, which leads to a very common problem that is the accumulation of dirt because of the charcoal and soot contained in the exhaust gases, producing a crust that prevents the valve from opening properly and narrowing the duct through which the gases pass. It usually occurs by circulating almost always in the city and especially at low speeds. Anyway, before going to the workshop, we can try to remedy it ourselves.

If we think the valve is dirty, we can drive at high speeds on the freeway so that the valve reaches a very high temperature which causes a kind of pyrolysis. In this way, part of the encrusted dirt will be burned. This also helps ‘regenerate’ the catalyst.

A visit to the workshop to clean or replace this valve mainly affects diesel vehicles.

The ‘elves’ of electricity and electronics

The truth is that breakdowns due to electrical faults do not usually give so much warning. The car stops and does not even give us the opportunity to “enjoy” the symptom of the pulls. Electrical failures create more headaches because they are usually complicated to find, and can range from failures in the spark plugs (which are very simple to replace) or wiring, to problems in the coils. If your car has more than one coil and one of them is damaged, the car will go to tripping. If it only has one coil, it won’t even start.

Everything becomes much more complicated and expensive, when there are problems that have to do with the electronic control unit or other more complex systems that require more comprehensive analysis and diagnosis, although it may also be a sensor that is giving a wrong reading (occurs half the time) or a connection is in poor condition.

Wear and tear is a very common problem

There are certain components that, either by the passage of time and miles or by misuse of them, can give some problem that other. Sometimes the solution is very quick, other times not so quick.

For example, in older cars the accelerator cable can be a source of pulling. Nowadays when we step on the accelerator, we send a signal to a device called a potentiometer, which sends an electrical signal to a valve, which is the one we activate by acting on the pedal. This regulates only the air flow and errors in its operation can cause jerks.


Finally, pulls can also come from problems in the gearbox. A breakdown in this element can be tremendously expensive, even a simple gasket, as it is very labor-intensive. Usually the pulls caused by the gearbox do not actually originate from the gearbox, but from the clutch. Excessive clutch wear can cause jerks at times, as well as vibrations, problems when changing gears and until the car moves out of place.

However, all the possibilities listed here can be prevented by regular maintenance. The manufacturers offer all kinds of information about it in the manuals, but if necessary, you can also contact customer service from there, they will give us the necessary information.