Car Starts But Wont Stay Running (Reasons and How to Fix It) | Rx Mechanic (2023)

“My car starts but wont stay running for long. What should I do? You probably have found yourself in such a situation. There are times when a vehicle runs for seconds and then shuts off by itself, or it can die while driving and won’t start. This may be a result of different failures in the parts of the vehicle. Identifying the exact possibility of this failure may be challenging when you do not understand the car systems. Many people have reported having similar failures such as “my 2000 BMW starts but won’t stay running” or “my car starts then die unless I give it gas.” This article is here to give solutions to complaints and answer all the questions related to these kinds of problems.

What the Reasons Car Starts But Won’t Stay Running:

As we stated, this failure involves many parts. You need to do several checks and fixes to know the exact causes of the faults and how to deal with them the right way.

Car Starts But Wont Stay Running (Reasons and How to Fix It) | Rx Mechanic (1)

Ignition System Problems: The 3 core elements for the car to start and run are fuel, spark, and air. If these three elements are available in the correct ratio, then the car will run smoothly and will not stop. If one of the three elements fails to decrease or increases slightly, the ratio changes and the car will not have a smooth running. After a while, it will shut off due to a bad spark or since the fuel support is not enough to sustain the engine and keep it running. This is what causes the car to start and then die when cold.

Bad Canister Vent Valve: The canister vent valve is part of the (EVAP) which is the evaporative emission control system. Its role is to route the vapors produced from the fuel and get them back to the canister and from the canister to the intake manifold. It then goes to the combustion chambers and gets fired by the spark plugs. The benefit of this system is to reduce fuel consumption. If this system fails, the car becomes unstable when idle and it turns off immediately after starting up.

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PCV Valve Failure: PCV (positive crankcase ventilation) valve is a valve designed to purge blow-by gases in the engine from the heating of the oil. It is resent to the intake manifold for lubricating and re-burning purposes. The PCV systems use a very tiny valve to get this job done. This valve goes open when purging the overloaded pressure. When this valve is defected and remains open, it results in an overflow of air streams into the intake manifold when idle or accelerated, causing the car to stall.

TPS Fault: TPS (throttle position sensor), is the sensor responsible for sending the throttle position to the ECU (engine control module). The importance of this signal is that ECU calculates the quantity of fuel to be provided to injectors to keep the right ratio between air and fuel in the mixture. When the throttle position sends the wrong signal to the ECU the fuel quantity delivered to the injector’s rail will be wrong; thus, the car may stall on idle. And you will notice that car starts but won’t stay running unless the foot is on gas.

ECT Sensor: This component helps the engine to protect itself and prevent its performance from getting by the engine temperature. The ECT (Engine Coolant Temperature) sensor is here to send information about the engine’s temperature to the ECU to adjust the mixture of air and fuel. When the ECT sensor is faulty, it sends wrong or false information about the temperature of the mixture, making it hard for the ECU to provide the right fuel quantity. The combustion will not be right, and this will cause roughness while driving the car and sometimes lead to stalling. The worst side of this kind of failure is that if the engine overheats the fans do not work at maximum speeds since they don’t have signals that the temperature is too high.

EGR Valve Defect: The EGR (Exhaust Gas Recirculation) is a system that recirculates part of exhaust gases back into the engine to reduce the temperature of the combustion chamber by getting this small portion of the exhaust gas back into the intake manifold. It is usual for the EGR valve passages to get stuck and blocked by the carbon build-ups. This prevents the valve from closing, thus making an extra air stream inside the engine that will cause stall and instability while idle.

Read: How to Clean Your EGR Valve?


Catalytic Converter: The catalytic converter’s role in the car is to revise, correct, and evaluate the work of the engine. It makes sure that the combustion is running well. The catalytic converter is usually attached to an oxygen sensor. The role of this sensor is to analyze the exhaust coming out of the combustion chambers and detect the percentage of oxygen in it. Depending on this info it corrects the air to fuel mixture to make successful combustion. The combustion is just balanced, and it’s neither lean nor rich. Therefore when the catalytic converter has a defect or is made of low quality, the sensor will not give accurate readings, and the air to fuel mixture will be affected negatively.

Wrong Injector Pulses: If you always feel that a car starts then sputters and dies, it could be as a result of wrong injector pulses. As we talked about before that to have successful combustion, three elements must be provided in specific quantities. They include the spark through the spark plugs, air going into the engine through air ducts and passing by the air filter, and finally the fuel supplied into the engine by injectors. Injectors perform this process via pulses. When the ECU gives a signal to the injector, it magnetizes the plunger and sprays fuel into the intake manifold or in the cylinder directly in some systems which are the GDI. Therefore, if these injectors are failing to give the right pulses, giving pulses at the wrong timing, or have a defect like over bleeding fuel, it prevents perfect combustion of this unsmooth running.

CMP\CKP: It is either called Camshaft Position Sensor or Crankshaft Position Sensor. You will never have a balanced performance out of your car if you have a defective camshaft position sensor or crankshaft position sensor. The work of the sensors is defining the timing and the spot of the crankshaft and camshaft. They also define the degree to of the valve opens to provide the air and fuel mixture to the combustion chambers. All this info is sent to the ECU for processing and analysis. It then decides on when to ignite the spark and when to spray the specific quantity of fuel. It also decides on the depth of the valve opening to be adjusted depending on the information.

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How to Fix the Problems

To fix any of the above problems, the first thing is to have the right diagnostic using the correct tools. It will take you time and cost trying to find the fault in traditional ways. Many of the defects mentioned above and failures cause the (MIL) diagnostics lamp to go ON. First, attach the diagnostic device compatible with your car model, and then start scanning the fault codes. Here we are going through some of the most popular fault codes that define the error precisely:

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Car Starts But Wont Stay Running (Reasons and How to Fix It) | Rx Mechanic (2)

P0300 – P0312: These codes define an error in the ignition system such as misfires. In this situation, you should start by changing spark plugs and then check again if the code will still appear. If it re-appears, the problem could be in the ignition coil or ignition coil cables. After checking the spark plugs remember to connect the Spark plug wire correctly to avoid any other defects.

P0335 – P0339: These errors usually represent a problem in the crankshaft sensor, which may vary from mis-programmed or false calibration sensors. In this case, get to the programming section and check the programming tools of the vehicle. Calibrate the sensor in this section. If errors are still there after re-programming, then you need to change the defective sensor depending on the code.

P0340 – P0349: Misaligned Camshaft sensor may fail the car operation resulting in stalling and stopping once starting. As stated in the crankshaft sensor, the same applies here.

P0400 – P0409: If an EGR error is found on the diagnostic platform, the first thing we need to disassemble is the EGR valve to clean its inside. You also need to check the sealing of the EGR. EGR should be cleaned in periodic maintenance to avoid faults and errors.

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P0500 – P0511: This error group represents errors in the throttle body and sensors assembled in it. This includes an idle speed sensor that is responsible for ensuring a minimum amount of air gets through the throttle body to keep the engine running smoothly. If carbon build-ups block this air passage, the car will stall in an idle state, or the car starts but dies after a few seconds. You have to keep your foot on the gas to keep the vehicle running. In this case, you are required to disassemble the sensors out of the throttle body. Using a throttle cleaner, spray on it to dissolve the stains and carbon it. You can then get it back into the car. In some models, the throttle body needs to be re-program after installation. Always check the shop manual before disassembling.

P0520 – P0523: This group of errors is related to the PCV system. If you find one of these errors, locate the PCV in your engine (usually in the cylinder head and connected with a hose to the throttle body). If you find that the valve is blocked, try to clean it. It is always preferable to change it since it is very cheap and easy to install. Note that failing to change the PCV valve may lead to adverse consequences such as the Head gasket Blown due to an overload pressure inside the engine.

P0087 – P0094: These errors are related mainly to the defects in the injection systems. From the error code, you can define which injector has the problem. After you know the defective injector, you can either clean it using the ultrasonic device or just change it. However, before changing the injector, inspect to see if the wiring harness is 100 % in a good state.

Final Words:

If your car starts then dies after a few minutes, or even seconds, you can be sure to find the reason for the fault in this article. The secret to ending this problem from the root has a proper diagnosis. I, therefore, suggest that you use the car-supported diagnostic tool to get full sensors scan, complete programming, and calibrating abilities. Finally, if you feel so confused about the problem, it is always a good idea to ask an expert for a solution. You will save time, and money, and get your car recovered easily and hassle-free.


What does it mean when my car starts but won't stay running? ›

This issue could be caused by an insufficient amount of fuel reaching the combustion chamber. For fuel issues, start by checking the fuel pressure. If it is low, look at the fuel pump, fuel pressure regulator, and injectors.

What could be the cause of an engine that fails to run after it starts? ›

The most common causes are problems in the ignition (for example, a bad ignition coil) or fuel system (for example, a clogged fuel filter). However, the source may also be a mechanical fault (for example, a leaking valve) or faulty components in other systems.

What are signs of a clogged fuel filter? ›

  • You have a hard time starting car. If the problem is the fuel filter, and it isn't changed soon, you may find that your vehicle won't start at all.
  • Misfire or rough idle. ...
  • Vehicle stalling. ...
  • Fuel system component failure. ...
  • Loud noises from the fuel pump.

How expensive is it to replace a fuel pump? ›

The average cost for a fuel pump replacement is between $220 and $1,062, depending on vehicle and age. Labor costs are estimated between $124 and $260, while parts are priced between $95 and $854. Estimates do not include taxes and fees.

What 3 things make an engine run? ›

Internal combustion engines use fuel to create an explosion (power) to move a piston down. Although there are many different designs to an internal combustion engine, there are three crucial components needed to make one run, a fuel to burn, oxygen to support combustion, and an ignition source to start combustion.

What 4 things make an engine run? ›

The cycle continues again and again, giving the car the power needed to run. Car engines use a four-stroke combustion cycle. The four strokes are intake, compression, combustion, and exhaust. The strokes are repeated over and over, generating power.

What causes a car to stop running? ›

Anything that interferes with the spark plugs doing their job can bring your vehicle to a stop. This can result from problems with the plugs, a camshaft sensor, plug wire, caps, rotors, ECU, crankshaft or distributor.

What are the symptoms of a weak fuel pump? ›

Is My Fuel Pump Going Bad? Here Are 8 Signs It Is!
  • Fuel Tank Noise. A damaged fuel pump might make a loud, whining sound that you'll hear from your gas tank. ...
  • Difficult Starts. ...
  • Sputtering Engine. ...
  • The Actual Stall. ...
  • Power Loss. ...
  • Surging Power. ...
  • Lower Fuel Efficiency. ...
  • Dead Engine.
1 Jul 2020

How do you clear a fuel blockage? ›

If your vehicle has an electric fuel pump, you can use a fuel system cleaner to clear any sediment buildup or blockage. If you have a manual one (usually found in older model vehicles), you can actually open the pump to clear debris out of its internal filter, though that isn't an option in most modern vehicles.

How much does it cost to fix a clogged fuel? ›

What Will It Cost? According to some auto service pricing sites, a fuel filter replacement service should cost between $50 and $175 for most cars to have the work done by a mechanic. If you are handy under the hood, you can order the part and do it yourself for between $10 and $70.

What are the signs you need a new fuel pump? ›

Seven Signs Your Fuel Pump Is Going Out
  • Sputtering Engine. Your fuel pump is telling you something if your engine starts to sputter once you've hit the top speed on the highway. ...
  • Overheating Engine. ...
  • Low Fuel Pressure. ...
  • Power Loss. ...
  • Surging Engine. ...
  • Gas Mileage Decrease. ...
  • Dead Engine.
10 Mar 2020

Is fixing a fuel pump easy? ›

Installing a fuel pump can be difficult – especially if you've got a full gas tank. Plus, because fuel is flammable, the task can be dangerous. If you decide to tackle the job yourself, make sure to take the necessary precautions and have a fire extinguisher on hand.

Can a fuel pump fail suddenly? ›

Fuel pump failures tend to be sudden and unpredictable, with few symptoms to warn the motorist that trouble is brewing. And the higher the mileage on the vehicle, the greater the risk of a fuel pump failure.

What gives power to the engine? ›

A vehicle's engine produces power by using a mixture of air and fuel to achieve combustion. The energy produced, as a result of the combustion, is then transferred to the wheels and the car moves. It is the job of the engine to perform this function repeatedly with maximum efficiency.

What can stop an engine from working? ›

Top 5 Reasons Car Engine Stops Suddenly
  1. Overheated Engine. This is one of the most common reasons why a car suddenly stops. ...
  2. Choked Catalytic Converter. The catalytic converter is a vital part of the exhaust system. ...
  3. Inadequate Transmission Fluid. ...
  4. Electrical Issues in Ignition/Computer. ...
  5. Loose Engine Bolts.
4 Jan 2021

What will make engine run better? ›

So, to keep your car running smooth, make sure you have the following engine-related services done regularly: Change the oil. Change the oil filter, air filter and fuel filter. Check the PCV valve for proper operation.

What parts make a car run? ›

The different parts that make up your car's engine consist of: the engine block (cylinder block), the combustion chamber, the cylinder head, pistons, the crankshaft, the camshaft, the timing chain, the valve train, valves, rocker arms, pushrods/lifters, fuel injectors, and spark plugs.

What are the 5 events of an engine? ›

A four-stroke cycle engine completes five Strokes in one operating cycle, including intake, compression, ignition, power, and exhaust Strokes.

What to do if car stops running? ›

What to Do if Your Car Stops Running When You're on the Road
  1. First, get to the side of the road. Your power steering is likely gone, and brakes as well. ...
  2. Try to restart. If this works, use the power to get to the nearest repair shop. ...
  3. Activate your emergency flashers. ...
  4. Call for help.
26 Sept 2019

What happens when fuel filter is dirty? ›

A clogged fuel filter causes low fuel pressure that results in a lean fuel condition and engine misfire. This can result in poor fuel mileage, rough idling and possibly cause the check engine light to come on. Once that light is on, it's time for a trip to the repair shop.

What does the car needs to keep it running? ›

Regular oil changes and oil, fuel and air filter changes all help make sure your car has what it needs to run without problems: clean air and clean fuel, plus fresh, uncontaminated oil to prevent wear and tear.

What would cause a car to shut off right after starting? ›

The most common reason your car starts then dies immediately is because of a lack of fuel in the engine. This often happens because there is a small amount of fuel in the fuel rail, which helps to start the engine. However, there is no fuel pressure to keep the engine running.

What does it mean if your car starts and then dies? ›

The most common and obvious reason your car may start then die is the fuel shortage in your engine. This happens because there's not enough fuel in the fuel rail, and there's no fuel pressure to keep the engine alive. The reason isn't always you forgetting to fill up your gas tank.

Why does my car shut off right after I start it? ›

One of the most common reasons for a car dying immediately after starting is when the fuel injection system is damaged, the internal combustion process will not run its course. Here's what you need to know: The air and fuel mix or ratio need to be in a specific proportion for the engine to start.

Why does my car run for a few seconds after turning off? ›

Answer: After the engine is shut off, its temperature rises. This excessive heat and pressure in the combustion chamber is what causes detonation, which ignites the residual fuel-air mixture in there.

How do I know if my fuel pump is bad? ›

Warning Signs of a Bad Fuel Pump
  1. The car won't start. If the vehicle is struggling to start or isn't starting at all, your fuel pump may be damaged or clogged. ...
  2. The car sputters or dies while driving. ...
  3. The engine surges while driving. ...
  4. You hear whining in the backseat. ...
  5. You notice lower gas mileage.
29 Apr 2022

How can I tell if I have a bad alternator? ›

7 Signs of a Failing Alternator
  • Dim or Overly Bright Lights. ...
  • Dead Battery. ...
  • Slow or Malfunctioning Accessories. ...
  • Trouble Starting or Frequent Stalling. ...
  • Growling or Whining Noises. ...
  • Smell of Burning Rubber or Wires. ...
  • Battery Warning Light on Dash.
24 Aug 2020

How do you unclog a fuel filter? ›

How To Clean Car Fuel Filters
  1. Locate The Fuel Filter. ...
  2. Ensure No Fuel Is Exposed To The Spray. ...
  3. Prepare A Container Under The Filter. ...
  4. Start Cleaning the Fuel Filter. ...
  5. Tapping Filter Surface. ...
  6. Spray Again and Dry. ...
  7. Install the Filter Back. ...
  8. Replace the Filter If Needed.
4 May 2021

How long does a fuel pump last? ›

The fuel pump is your vehicle's unsung hero. It takes gas from the gas tank and sends it to the engine so your car, truck, or SUV can start and run. Your vehicle's fuel pump should last at least 100,000 miles or more.


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