Diagnosing a Car That Dies While Driving or While Idling
Dan Ferrell writes about DIY car maintenance and repair. He has certifications in Automation and Control Technology and Technical Writing.
A number of systems in your car can cause stalling issues when you least expect them.
When Is Your Engine Stalling?
You may experience different symptoms:
- On deceleration, engine rpms may fall below normal idle speed and stall.
- When reaching a stop light, the engine may jerk and die.
- While driving, the engine may suddenly shut off.
Is Your Check Engine Light On?
If your check engine light (CEL) is on, that is your first place to start. Download diagnostic trouble codes from your computer. The codes may point you to the component or system behind the fault.
However, even if you don’t see the CEL come on, the following section headings describe the most common circumstances under which an engine may stall and show you the most common systems or components where the fault may be located.
If your vehicle dies under particular circumstances (e.g., only when warmed, when cold, at idle, while moving, or on deceleration), take this into account during your diagnostic. The way your engine fails can give you important clues about the type of trouble the engine is experiencing.
Car Systems That May Cause Stalling
Diagnosing a car that dies while driving or at idle can be difficult. The fault may originate in one or more of several systems:
- Fuel system
- Intake air system
- Charging system
- PCV system
Index: Diagnosing Your Stalling Problem
- A Warning Light Appears on the Dashboard
- My Engine Shuts Off and My Lights Cut off While Driving
- My Engine Dies After a Few Minutes of Operation
- My Engine Shuts Off When I Reach a Stop Light
- My Engine Shuts Off While Idling
- My Engine Shuts Off While Driving, But I Can Restart It Again
- My Car Suddenly Dies
- Getting More Help
A warning light on your car dashboard can give you a clue to diagnose your engine stalling issue.
1. A Warning Light Appears on the Dashboard
A charging system problem is one of the most common sources of stalling.
Charging systems give some warning when they fail. Usually, you’ll see a warning indicator on your dashboard, like a:
- battery light
- voltmeter indicating less than 12 volts
- ammeter showing low current
- charging system warning lamp
- «Service charging system» message
- check engine light
Depending on the particular fault, one or more electrical accessories will not work properly or at all.
The indicator(s) may be warning you that the charging system is not producing sufficient current for your battery and other electrical circuits to operate correctly. Or that a diagnostic trouble code has been stored.
Often, the fault is in the alternator or voltage regulator.
Once your charging system fails, you may be able to drive about 30 minutes, if your battery is in good health. After that, your battery power will be depleted and you’ll be unable to restart the engine.
Read More from AxleAddict
Why Is My Car Overheating When Idle?
Why Is My Car Shaking?
Components to Check:
On some vehicle models, the charging system may be controlled by the car’s computer or electronic control unit (ECU). In this case, a charging system problem will trigger a diagnostic trouble code.
This code can be of great help when diagnosing a system problem. If you see the CEL on, download the trouble code(s) using a scanner or code reader. If you don’t have a scanner, your local auto parts store may download the codes for you.
However, if the CEL is not on, you still may diagnose the problem. Here are some components that you may want to check:
- Check the battery case for damage.
- Check the battery terminals and cables. The most common issue is corrosion around the battery posts and terminals, or a loose cable. Either of these will prevent the charging system from properly charging the battery. Also, the battery may be faulty. So have the battery checked, if necessary.
- Check the drive belt. A loose or worn drive belt may fail to properly charge the battery or run the alternator. Check the belt for damage, proper adjustment, and inspect the pulleys for proper alignment.
- Check the charging system circuit, including wires, connectors, fuses, and fusible links.
- Have the voltage regulator and alternator checked for proper operation.
Corrosion causes electrical resistance and prevent the alternator from charging the battery.
2. My Engine Shuts off and My Lights Cut off While Driving
You may notice that every time you drive over a bump on the road or take a sharp turn, the radio, lights and engine suddenly shut off. This is not only frustrating but a safety issue.
After a few minutes, the engine and the rest of the electrical accessories may start working again.
Although this may seem like a catastrophic problem, the fix can be something simple.
What to Check:
- Engage the parking brake, start the engine, and let it idle.
- Pop the hood open.
- Wiggle the battery cables, including the small wire that connects to the car’s body, if your vehicle has one.
- If the engine shuts off and the headlights stop working while you do this, you are dealing with a loose, corroded or frayed cable or wire. You’ll need to repair or replace the wire, cable or connection.
Other Potential Problems Include:
- A worn out or faulty ignition switch. The headlights will still work.
- A blown fuse or fusible link. Your lights and other accessories may still work, but the engine may not restart.
Faulty ignition modules can lead to stalling issues when components reach operating temperature.
3. My Engine Dies After a Few Minutes of Operation
You start your vehicle and after a few minutes of driving, the engine shuts off. The engine won’t start until it cools, just to die again after a few minutes of driving.
Lights, radio and other electrical components will still work.
What to Check for:
- faulty ignition coil
- bad ignition module
- faulty crankshaft position sensor
- bad fuel pump motor
Coils and small electronics in ignition modules, motors and ignition coils may develop electrical «opens» that won’t show up until the component warms up and wires inside the component expand, causing the open to appear.
To test for an open coil on a magnetic-type crankshaft position (CKP) sensor (with one or two wires) or ignition coil (on single coil models with a distributor):
- Remove the sensor or coil from the vehicle, if necessary.
- Test the sensor resistance; or the primary and secondary ignition coil resistance.
- Compare your results to the specifications in your vehicle repair manual.
- Heat the sensor or ignition coil moderately using a hot air gun or hair dryer.
- Repeat step number 2.
- If the readings differ or the sensor or ignition coil reads infinite resistance, replace the component.
Look for the idle air control valve or throttle position sensor hooked up to the throttle body.
4. My Engine Shuts Off When I Reach a Stop Light
An engine that stalls when you reach a stop light or while idling may point to a faulty idle air control solenoid (IAC). The computer uses the IAC solenoid to bypass the throttle valve and inject more air, depending on engine operating conditions.
A common problem with air passages in the throttle, and the IAC valve itself, is carbon, dirt or fuel varnish buildup. If air can’t go through the air ports when needed, the engine may stall when you reach a stop or while the engine is idling.
To Check the IAC Air Passages for Clogging:
- Locate the IAC around the throttle body.
- Unplug the IAC solenoid electrical connector.
- Remove the solenoid from the throttle body.
- Check the air passages for carbon buildup and clean them as necessary.
Another possible problem, besides clogging, is that the IAC motor or its circuit may have failed.
If You Need to Test the IAC:
- Remove the IAC solenoid from the throttle.
- Connect direct battery power to the solenoid using jumper wires.
- If the solenoid doesn’t respond, replace it.
The IAC motor can also be checked with an ohmmeter. Consult your vehicle repair manual, if necessary.
Other faults can also trick the computer to operate the IAC solenoid when it should not. For example, a throttle position (TP) sensor that is sending incorrect signals to the computer may cause it to close the IAC solenoid when it shouldn’t, stalling the engine. The TP sensor or its circuit may be faulty.
Also, depending on your particular vehicle make and model, check for a loose engine speed sensor or bad sensor, especially if you’ve noticed a misfire at driving speeds.
The next video shows a vehicle with this type of problem. Deceleration when coming up to a stop light seems to kill the engine.
5. My Engine Shuts Off While Idling
This condition is similar to the previous one, but the issue here may be more persistent. You may even see the check engine light come on. Different components may cause your engine to shut off at idle.
What to Check:
Usually, this points to a vacuum leak, especially on vehicles with a mass air flow (MAF) sensor:
- brake booster
- EGR system or valve stuck open
- PCV valve stuck open
- Intake or throttle gasket
If your CEL is on, you may get trouble codes P0171, P0174 or P0300.
Depending on your particular model, you may also want to take a look at the engine speed sensor for a loose wire or bad sensor, especially if you’ve noticed a misfire while driving.
Also, the engine may stall at idle when cold. This may point to a faulty sensor that is sending wrong data to the computer or a system with a worn or faulty component.
What to Check:
- Bad fuel pressure regulator
- Bad MAF sensor
- Faulty manifold absolute pressure (MAP) sensor
- Faulty engine coolant temperature (ECT) sensor
- Failed throttle position sensor (TPS)
- Intake vacuum leak
Often, a bad sensor will trigger the check engine light (CEL). Even if you don’t see the light on, scan your computer for trouble codes. A pending code may help you focus on a system or component that may be causing trouble.
Faults in the fuel system, like a clogged fuel filter or faulty fuel pressure regulator, can decrease fuel volume to the engine and cause stall issues.
6. My Engine Shuts Off While Driving, but I Can Restart It Again
Here, the engine may stall while the car is moving, and, sometimes, while idling. Often, the vehicle gradually dies. You may feel your car jerk a bit before dying, as if your car has run out of gas. The fault may be in the fuel system.
What to Check:
- Clogged fuel filter
- Faulty fuel pressure regulator. You can test for fuel pressure yourself using a fuel pressure gauge. Look up the pressure specifications for your particular car make and model in your vehicle repair manual. If you don’t have the manual, you can get a relatively inexpensive one from Amazon. Haynes manuals come with step-by-step procedures and illustrations for many troubleshooting, maintenance and component replacement projects you can do at home.
- Fuel pump. If you haven’t replaced the fuel pump in the last ten years, the pump may be worn and unable to deliver the correct amount of fuel the engine needs above idle speeds. Check the fuel pump if your vehicle stalls when stopping at a red light and then starts right back up.
Ignition system problems can suddenly cut off electrical flow to engine electrical circuits.
7. My Car Suddenly Dies
Often, a car may suddenly die on the road or while idling. Unlike the cases discussed above, this failure feels as if the ignition switch was turned off. Headlights and other electrical accessories still work.
Depending on your particular vehicle year and model, the problem can be in the ignition system itself, or a sensor your car computer depends on to keep the ignition system functioning.
What to Check:
- Faulty crankshaft position (CKP) sensor
- Problems in the CKP circuit
- Bad ignition switch or circuit
Faulty primary ignition system. Depending on your particular system this may include:
- ignition switch
- ballast resistor
- ignition coil (single coil with a distributor)
- ignition control module
The problem can point to bad contacts in the ignition switch or some other component’s electrical connector.
If the fault prevents the engine from restarting, a component, connector or wire has completely failed.
If the problem shows up when the engine warms up and disappears once the engine has cool, check section 3 above, «My Engine Dies After a Few Minutes of Operation.»
A brake booster with vacuum leaks can also lead to engine stalling issues.
8. Getting More Help
There are many different reasons that a car might die while driving or at idle. Some reasons depend on your particular model; other times, it is a factory problem.
What to Check:
Vehicle manufacturers post technical service bulletins (TSB) that address an issue with a particular system or component in a particular model. And this may include issues for a car that stalls while driving or at idle, for example, a faulty computer program or a defective component used in a particular model.
If you find it difficult to find the source of a particular stalling problem while driving or at idle, check for a possible TSB for your particular model. Search for it online or call your local dealer’s service department.
For more help, check this other post that takes a similar approach to diagnosing some specific cases on stalling issues. Also, if your engine stalling problem is accompanied by idle performance issues, this other post on rough idle may help as well.
This article is accurate and true to the best of the author’s knowledge. Content is for informational or entertainment purposes only and does not substitute for personal counsel or professional advice in business, financial, legal, or technical matters.
Questions & Answers
Question: I have a 2004 Pontiac Grand Prix. It struggles badly. My car dies randomly as I’m driving down the road. The lights and everything stay on but are dim. It always starts up again. There are never any warnings or check engine lights either. Could my car’s random dying be the ignition pack?
Answer: Intermittent faults are hard to locate, but you seem to have a sensor or power source with a loose connection. Download trouble codes, even if the check engine light is not coming on. I’d check the voltage drop on the battery cables, engine grounds and key sensors like crankshaft and camshaft position sensor.
These other two posts may help:
Question: What could be my issue? TIA. I have a 2001 Acura MDX. It will very randomly completely lose power (as if I were to turn the car off) while driving and then comes back on. There have also been times when it dies out of nowhere at a stop sign/light. No check engine light is on. Any tips or suggestions would be greatly appreciated.
Answer: If the engine dies as if you turned off the ignition key, look for a loose connection. It may be a ground wire or engine strap. Have the engine idling and start wiggling engine and battery ground wires and straps. Also, this other post may help:
Question: What can be the problem? Volkswagen Golf 6 TSI cuts while driving and starts after a while and has ACC problems, especially when it’s hot. Then he struggles to start again. The injector was changed. Petrol pump, lines, and filter changed this year but still doing the same thing. Engine light is on orange.
Answer: The best way to start is to download the diagnostic trouble code. That should pinpoint the system or components you need to start checking. The problem could be temperature related. It could be an ignition module, a crankshaft or camshaft sensor.
Question: My truck dies while idling at a stoplight and has to be jumped to restart. What is the likely cause?
Answer: First make sure the drive belt has the correct tension. Have the charging system, alternator and battery checked. These are the most common problem sources.
If necessary, check engine grounds:
And charging system voltage drop:
Question: My friend’s car keeps turning off and on while driving. We don’t know why all the lights come on when it restarts itself a second later. What could cause my friend’s car to turn off while driving? It’s a 2009 Chrysler. No idea the make and model of it. The mechanic says something is wrong with the starter.
Answer: Intermittent faults are kind or hard to diagnose. There seems to be a loose connector or wire, possibly in the ignition system or a sensor that cuts off and interrupts communication with the computer. Check the ignition circuit first and see if there’s a loose wire in there. Also, try downloading trouble codes, even if the check engine light is not coming on. There could be a pending code that may help you here.
Question: I was driving on the highway when all of a sudden my engine light came on and car turned off. The car still would turn over but not start. Just filled up the night before. Could this be a fuel pump problem or fuel filter problem?
Answer: It’s possible, but download the trouble codes from the computer. That should give you better guidance to the system with the problem. It could also be an ignition system or sensor problem.
Question: I am having a serious issue with my BMW X6 2011 model. Originally, it was the fuel pump. That has been replaced. Since then, several alerts came. Firstly, battery no charging (changed); then alternator (changed); but I keep getting stuck on the road while driving, with several alerts popping up (traction, ABS, with radio and AC shutting off). What do you think could be the reason?
Answer: The traction control system works in conjunction with the ABS system. There could be a problem with the wheel speed sensors (dirty or faulty), the harness connector or a wire in the circuit; however, there could also be a problem with the TCS computer. Scan the computer for trouble codes, this can guide to the source of the problem. Always make sure to test suspect components or wires before swapping parts to make sure you have located the source of the problem.
Question: I have a 2008 Dodge Ram 1500, 4.7L. Sometimes the engine stops while driving but will restart. Transmission was overhauled. It has new wires, new spark plugs, O2 sensor was replaced. What could be the problem?
Answer: If the problem is intermittent, there could be a sensor with a loose connector or wire. Try downloading trouble codes and see if you find any pending codes that can guide you here. This other post may help as well:
Question: I have a 2017 Jeep Cherokee Sport. For a few months, the interior lights flicker when the engine is running and a door is opened. Recently the vehicle has simply died while driving or at a stop, it is hard to start afterward but does start. What could it possibly be? I was thinking maybe the alternator but I really don’t know.
Answer: If this only happens with the engine running, there could be a faulty ground. Check voltage drop on the charging system and engine grounds. These other posts may help:
Question: I have a Chevy Cobolt. My CEL is on, and it idles low. Once you start driving it, after its been sitting for 20-30 minutes, it will idle down really low, especially when coming to a stop, and stall. I have to throw it in Neutral. Then back into drive. Any ideas?
Answer: Start by downloading the trouble codes. See what the computer is reporting as the problem, but don’t replace any components yet until you test the system or components reported with the code. This other post may help too:
Question: While driving, my car shuts off and restarts again without any issue. Before shutting down, it shows some signs as the fuel light flashing, not constantly but after a 3-5 minute gap. Why would my car’s fuel light flash before the car shuts down?
Answer: If you have plenty of fuel in the tank, then there could be a problem in the fuel system. First, make sure the fuel cap is properly installed and in good condition. If in doubt, have it checked or replace it. Another possibility is a leak in the fuel Evaporative Emissions (EVAP) control system. This system deals with fuel vapors coming from the fuel tank. The vapors are routed to the intake system. If there’s a leak in this system, the fuel light will flash.
Question: The truck died but lights still work. 1979 Ford F-150. Any clues what might the problem be?
Answer: If the engine cranks but won’t start, check for good spark and fuel pressure. These are the most common systems involved. Also, you may be dealing with a bad sensor. Download trouble codes, even if the check engine light is not on. You may find a pending code that can give you a clue about the issue. This other post may help as well:
Question: My Ford Edge just died while driving and would not restart. The mechanic said it was wires and fuses, but my brother-in-law said that’s bunk. Does my brother-in-law know what he’s talking about?
Answer: The problem may come from a sensor or component that stopped working or a fault in a circuit. Download trouble codes and see if you got a code that may guide your diagnosis, even if you don’t see the check engine light on. Check for spark and fuel system pressure:
And check the crankshaft and camshaft sensors.
Question: Ran diagnostic code P2106. 2004 Ford F-150 4.6L. Ford place has changed throttle body and computer truck starts and idles fine but when driven, it stalls every 30 to 60 secs. What is wrong?
Answer: The problem could be in the circuit, or another condition is causing the fault. In this case, it’s helpful to have the freeze-frame data when the fault occurs. Your mechanic can diagnose this with a scan tool. Also, if the code wasn’t erased after the throttle actuator system was fixed, it can continue with the fault. If there are other codes present, take a look into those codes first.
Question: My 2008 Cadillac SRX randomly shuts off while driving when stopped at a red light and even when just sitting idling. I changed sensors and actuators. Don’t know what else to look at. Any ideas?
Answer: These kinds of intermittent problems are sometimes hard to diagnose. But this other post may give you some ideas on where to look,
Make sure to download trouble codes, even if the engine light is not on.