How to Determine Why a Car Stalls at Intersections

Last Updated: November 5, 2020 References

There may be lots of reasons a car stalls at intersections, including low automatic transmission fluid levels, moisture in your gas, broken sensors, or issues with the EGR valve.

Method 1

Method 1 of 4:

Low Transmission Fluid Level

1
Check the dipstick on the automatic transmission.^{[1]
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Research source} Check the owner's manual for the correct procedure for your vehicle — generally, manufacturers prefer testing with a warm engine.^{[2]
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- Be sure to check the fluid when parked on a level surface. Do your best to not allow any lint or dirt to contaminate the dip stick before reinserting.

Method 2

Method 2 of 4:

Clogged Catalytic Converter

1
Look for stalling, no power when accelerating. The check engine light will likely be on.^{[3]
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2
Look under the car at night after the vehicle has been running for a while. If the catalytic converter is glowing, it's probably clogged. You will have to replace the converter if you find this to be the problem.^{[4]
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Method 3

Method 3 of 4:

Broken O2 Sensors

1
Look for initial idle OK after a cold engine start-up, but a warm engine idle will surge and stall.
2
Take your car in to get a reading.^{[5]
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Research source} After a few thousand miles of this, most cars will turn on the "check engine" light. You can take it to any AutoZone, Advance auto parts, Napa, or O'Reilly's (but some places may only check cars made after 1996, so call and check first) and they will read the codes for free. There can be any number of reasons for the "check engine" light to come on, so it is good to check. Codes complaining of unexpected lean mixture is a good indication of O2 sensor failure. O2 sensors will typically last 60–75K miles. The good news is that you can buy an O2 sensor online for around $50 and they are generally pretty easy to replace.^{[6]
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Research source} Another possible reason is that the engine is idling too low (the idle is adjustable) or the control module is going out, which is relatively inexpensive and easy to access and fix.

Method 4

Method 4 of 4:

Clogged/Stuck EGR Valve

1
Look for the Engine Code Error (EGE) P1406.If the EGR valve is stuck open, the car will run sluggish at lower RPMs. If the valve is stuck closed, the car won't run well at higher RPMs (on the highway).
2
Try cleaning the excess carbon out of the EGR valve first. It may just need to be cleaned and not need replacing.^{[7]
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Research source} If cleaning the EGR valve does not work and you are still getting code P1406, the EGR valve needs to be replaced.^{[8]
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Community Q&A

Question

My car started for a minute or two, then shut off. Now it won't start at all, but it sounds like it is trying to start. What might the problem be?

Community Answer

It's probably something with the fuel transfer system pump filter or maybe the spark plugs.
Question

Where is the screw to turn the idle up?

Community Answer

On the side of the EGR valve/throttle body, there's a cable that connects to a screw where you can adjust the idle.
Question

My 2000 Nissan Sentra doesn't want to idle -- when it does, it stalls when giving it gas.

Community Answer

Clean your throttle body and intake manifold. Most likely the AFRs (air to fuel ratio) may be off, causing it to run too rich or too lean. Buy a can of throttle body cleaner and spray it in and around generously, while the vehicle is running. If that doesn't work, try running some seafoam through a vacuum hose while vehicle is running and also pour some in the gas tank. The fuel injectors could be clogged or need to be cleaned.

Warnings

Use the proper type for your vehicle. Do not overfill.

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Inspect the EGR valve while outdoors, or in a well-ventilated area, to reduce exposure to fumes from the carburetor cleaner or exhaust.

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Often, you will have to reach into cramped, hot spaces to check your fluid. Check your manual for the proper location. Take care not to be burned by engine parts. Wear long sleeve shirts or gloves as appropriate. Also, when adding fluid, it is a good idea to use a funnel with an appropriate length of neck.

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