Stalling at low speeds and idle.

I recently had autozone run the computer on my truck and it came back as failing cat and ignition coil. I eliminated the cat and replaced the ignition coil. The truck runs much better, but i hit that same issue with the killing. again, it runs better, but the killing hasnt stopped. should i replace the wire from the ignition coil to the distributor cap? i did a full tune up about 3 years ago so all the wires and spark plugs were replaced. i dont remember if i replaced the distributor cap or not. i think i have it narrowed down to either the wire from the ignition coil to the distributor cap, o
Experienced mechanics share their insights in answering this question :
I would recommend checking the idle air control valve to see if it is dirty or working properly. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about ~800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle. You can test the functionality of the valve by checking its electrical resistance if you have access to an ohm meter. To do this, disconnect the IAC valve, connect an ohmmeter to pins 2 and 3 of the valve. If you get a resistance value between 10-14 ohms, it indicates IAC valve is working as it should. Next, connect the ohmmeter to pins 1 and 2. If you do not get a resistance value between 10-14 ohms, the IAC valve may need to be replaced.

How to Identify and Fix Common car Problems ?

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The most common reasons a Dodge Dakota engine stalling are the fuel system, the air intake system, or the ignition system. Search our network of RepairPal Certified shops near you to speak with a technician about your issue. The distributor pickup plate commonly fails causing intermittent stalling, or…
Typically, the idle speed will be set at a value in the range of 600 to 800 RPM, but the exact value will depend on the number of engine cylinders and whether the vehicle is equipped with a manual or automatic transmission.
The most common reasons a Dodge Dakota has rough idle are a vacuum leak, an issue with the spark plugs, or a problem with the ignition coil.
There are three major causes for a stalled engine: A lack of fuel, a lack of air flow and improper ignition. Running out of fuel is one of the most common causes of engine stalling, but dirty fuel injectors or a plugged fuel filter can also be the culprit. Your engine needs air to run properly as well.
The most common sensor which can lead to your car stalling is the manifold absolute pressure sensor (MAP) or the mass air flow sensor (MAF). Most cars typically have one or the other.
A bad IAC can potentially lead to stalling, which can compromise vehicle safety. Plus, you won`t pass a state emissions test if the check engine light is on due to a bad IAC. As such, you should replace a faulty IAC as soon as possible.
In most cases, this will occur due to an obstruction of fuel or the inability to correctly mix the right ratio of fuel to oxygen. This could be due to dirty or clogged fuel injectors, throttle body or a mass air flow senor or idle control valve that is faulty or needs to be cleaned.
An idle air control valve, also called an idle air sensor control motor, is an electrically operated valve that controls the amount of air that bypasses the throttle plate in cars with a fuel injection system [source: Autozone]. This causes the idling speed of the engine to change as needed.
In most cases, this will occur due to an obstruction of fuel or the inability to correctly mix the right ratio of fuel to oxygen. This could be due to dirty or clogged fuel injectors, throttle body or a mass air flow senor or idle control valve that is faulty or needs to be cleaned.
If you have a newer model car, the reason may be a malfunctioning electronic sensor or an imbalance in the air/fuel mixture. However, for older model cars, it could be the idle speed control actuator, a faulty alternator, or even a dead battery.

Relevant Questions and Answers :

the most relevant questions and answers related to your specific issue

After replacing the power steering pump there was a low idle, idle screw is all out, running rich, and idle speed doesn’t change.
ANSWER : Hi there. The engine has a vacuum leak and is causing the engine to stumble down on the idle. Check all of the vacuum hoses and the brake booster for any leaks. The engine is rich for it’s not burning all of the fuel properly and may also have bad spark plugs. If you need further assistance with engine not adjusting the idle, then seek out a professional, such as one from Your Mechanic, to help you.

Idles between 500rpm and 1300 rpm. Main concern is low rpm. Belt or pulley chirping mainly at low rpm Drives perfect but Idles bad
ANSWER : Hello. From what you describe it would appear that your vehicle may have more than one issue.

Belt chirping is usually caused by a worn belt or tensioner. If either component wears out the belt may loosen and chirp when the engine is started, or cold.

The low rpm low quality idle can be caused by a few different things. I would look at the idle air control valve, as that is the component that maintains the vehicle idle, and at any vacuum hoses that may be cracked or damaged, and possibly leaking. This is more likely for older or high mileage vehicles.

If you’re unable to pinpoint the issue yourself, consider YourMechanic, as one of our mobile technicians will be able to come to your home or office to diagnose your starting issue firsthand and make the necessary repair to your car.

Very low idling during cold start, stalling engine, 2007 Toyota Corolla
ANSWER : The first thing you should do is scan the engine and repair any codes. Have the fuel vapor system checked to make sure you do not have any problems with a leaking purge valve leaking vapor into the intake when the engine is not running and then leaks even more vapor when you start up the vehicle. If system is not leaking, then have the spark plugs replaced after having the throttle plates cleaned and the combustion chamber and valves cleaned. The valves may have some carbon build up on them that will cause low rough idle even stall cold. If you want to have this done, consider YourMechanic, as a certified technician from YourMechanic, can come to your home or office to diagnose the cold start and let you know what should be done.

Car sporadically stalls when at very low speed or stopped 2011 Volkswagon Jetta
ANSWER : Hello – it would be useful to know what the "successful" dealer did that improved the hard starting problem. These problems may or may not be related. What is the behavior when it shuts off? Can you start it right back up immediately, or does it remain "dead" for a few minutes (something needs to cool down?)? Do you have spark at the plugs after it shuts off (if it refuses to crank right back up)? Spark failure after a stall might be a crankshaft position sensorthat is beginning to fail. Random electrical faults due to bad wiring are a nightmare to diagnose, but the clues are still important in doing so. I recommend a stalling inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.

overheated twice and stalled. Changed thermostat now is fine. Now is stalling at low speeds. Any ideas?
ANSWER : Hi there. Typically engine overheating and issues you are describing are caused by damage that may have occurred during the overheating period. For example, if the engine cylinder heads got too hot, it’s possible that the head gasket may have warped, causing coolant to leak into the engine and cause performance problems. It’s also common for excessive heat to damage electrical harnesses and critical engine sensors or components that monitor and control the fuel and ignition system. The best way to resolve this problem is to have a professional mobile mechanic complete a car starts then dies inspection.

Car is chugging at low speeds and then stalls when I stop.
ANSWER : This may be related to a dirty or failing idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer which will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed. This is all controlled by the idle air control valve. When the engine RPM drops below the normal range of 750-800 RPM (for most cars), this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and repair your idle air control valve.

Low idle problem
ANSWER : Hi there. If the idle control valve is good then the problem is typically caused by a vacuum leak or an issue with the throttle body. I usually check the engine for vacuum leaks first. It may be a vacuum leak in one of the hoses or in the intake manifold. The intake gasket is a common failure.

If there are no vacuum leaks, then I would test the throttle position sensor to make sure it is reading correctly. If it is also reading fine, then I would check the throttle body itself. If the bore or plate is worn then this will occur. If you want to have this low idle problem inspected, consider YourMechanic, as a certified mechanic can come to your home or office to diagnose and repair this.

Problem with speed. No check engine light on but when accelerating speed, it decreases then speeds right back up. No stalling at all
ANSWER : Hi, thanks for writing in. This is a common problem associated with fuel/air delivery which is very commonly related to what is called a mass airflow sensor. This monitors the flow of air intake into the throttle body as it is mixed with fuel to deliver the right air/fuel mixture into the motor. When this is not working properly, this will cause this kind of hesitation or surging when trying to accelerate. I would recommend having an expert from YourMechanic come to your home or office to confirm a diagnosis on the issue and make or suggest the necessary repairs or replacements.