My engine stalls at idle?

Tiny
WHITEBRAD
  • MEMBER
  • 2008 CHEVROLET IMPALA
  • 3.6L
  • V6
  • FWD
  • AUTOMATIC
  • 109,000 MILES
When I'm driving it's fine. It's only when I'm idling at a light or after a drive on the highway. It's almost like a quick bog down but then it bounces back real quick. It hasn't died on me and hasn't thrown a check engine code so I'm kind of stuck and I'm wondering what I need to do to fix it, any suggestions would help please and thank you
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Tuesday, February 23rd, 2016 AT 2:31 PM

32 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,468 POSTS
It sounds like you have a vacuum leak, can you hear a hissing noise, please follow this guide to help you check for one, if it seems okay get back to me so we can continue.

https://www.youtube.com/watch?v=xN5pcM-5bso

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Monday, March 7th, 2016 AT 3:44 PM
Tiny
AUDREY KIDNEY
  • MEMBER
  • 1 POST
  • 2007 CHEVROLET IMPALA
  • 3.5L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 200 MILES
In morning when car is started I have to hold foot on gas to get it to run and will not idle for a little while when I put foot on brake to put it in gear it stalls. I do this about 3 or 4 times and finally it will idle properly after I really rev up the engine. Sometimes a black puff of smoke comes out and then it will idle and run properly for the rest of the day.I seem to have this problem when it is cold the most. Code says system too rich. Where do I start first in your opinion?
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Wednesday, January 20th, 2021 AT 5:33 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,922 POSTS
Hi,

The black smoke is an indicator that the fuel mixture is too rich. Chances are it is related to the fuel pressure regulator. Do me a favor. Here is a link that explains how to test fuel pressure. Do this and let me know the results.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/engine-black-smoke

There could be other issues causing it; however, this is where I would personally start. Here are the manufacturer's specs for pressure:

2007 Chevrolet Impala V6-3.5L
Pressure, Vacuum and Temperature
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Fuel Pressure Specifications Pressure, Vacuum and Temperature
PRESSURE, VACUUM AND TEMPERATURE
Fuel Pressure (Key ON, Engine OFF) .................... 384-425 kPa (56-62 psi)

____________________________

If possible, let me know what code or codes were pulled. Often times I can tell what a more likely cause would be.

Take care and I'll watch for your reply.

Joe
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Wednesday, January 20th, 2021 AT 5:33 PM (Merged)
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
There are a couple things that this could be. Most likely you have a vacuum leak. It is odd that it would only set one bank for the lean code, but I would start with this:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

The next thing is a possible throttle issue. However, your vehicle has an electronic throttle so it may just need to be cleaned.

https://www.2carpros.com/articles/throttle-actuator-service

I attached the info on this code as well. You could have an issue with an o2 sensor.

Run through this material and let me know what you find. Thanks
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Wednesday, January 20th, 2021 AT 5:33 PM (Merged)
Tiny
RANDOLPH DESHAWN YOUNG
  • MEMBER
  • 1 POST
  • 2006 CHEVROLET IMPALA
  • 3.5L
  • V6
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
Car shuts down when in gear.
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Wednesday, January 20th, 2021 AT 5:33 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 107,922 POSTS
Welcome to 2CarPros.

Many things can cause an engine to stall at idle or when placed in gear. Engine vacuum leaks, a faulty idle air control valve (IAC), dirty throttle body, and so on.

With that in mind, can you tell me if the check engine light is staying on when the engine is running? If it is, I recommend scanning the computer to retrieve diagnostic trouble codes. If you are able to retrieve codes, it will point us in the right direction.

As far as possible things, here is a link that explains the most common causes of a stall at idle. Take a look through it and see if anything helps.

https://www.2carpros.com/articles/stall-at-idle

Also, here is a link that explains how to check for engine vacuum leaks:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Here are links that shows in general how to replace an IAC and service it. I would suggest removing it and checking for carbon build up or dirt where it mounts.

https://www.2carpros.com/articles/idle-air-control-valve-service

https://www.2carpros.com/articles/how-to-replace-an-idle-speed-control-motor-iac

Let me know if that helps. Also, let me know if there is anything you can do to prevent the engine from stalling.

Take care,
Joe
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Wednesday, January 20th, 2021 AT 5:33 PM (Merged)
Tiny
LAWANDA WILEY
  • MEMBER
  • 1 POST
  • 2004 CHEVROLET IMPALA
  • 3.4L
  • 124,000 MILES
I replaced the spark plugs, I replace the wires, I replace the three coils and it still will not stay running.
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Wednesday, January 20th, 2021 AT 5:34 PM (Merged)
Tiny
JDL
  • MECHANIC
  • 16,098 POSTS
How long since overall tune-up? Any applicable trouble codes? To check codes yourself, at the least you need an obd2 code reader. Did you visually check for spark, use a spark tester. Use a gauge and check proper fuel pressure. Also, check fuel injector pulse.

If start and stall, have to check security system. Is there a security lamp on the dash that is on or flashing?
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Wednesday, January 20th, 2021 AT 5:34 PM (Merged)
Tiny
RENEE L
  • ADMIN
  • 1,257 POSTS
Hello LAWANDA WILEY,

I am sending you some information to help you with the advise JDL gave you. These are links to a couple of articles form this site that feature written step by step instructions and pictures explaining how to do the scan yourself, also I have included a link to our YouTube channel with a how to video on code scanning. In addition I have included a link to another article from this site explaining the process of checking the fuel pressure yourself. If you decide you would like do this yourself you can purchase a fuel pressure gauge online from sites like Amazon.com. Most scanners are fairly inexpensive to purchase. Once you have the codes please get back to us so that we can further assist you. We are always happy to help.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

https://youtu.be/YV3TRZwer8k

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Thank you for visiting 2CarPros.com.

Kindest regards,

Renee
Admin
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Wednesday, January 20th, 2021 AT 5:34 PM (Merged)
Tiny
IMPALABLUES
  • MEMBER
  • 1 POST
  • 2004 CHEVROLET IMPALA
  • 138,000 MILES
Car was running fine and all of a sudden one day it started having problems starting. Once I had it started it ran great for about 3 days. Now it's having problems starting and stalls when I slow down. I had the egr and pcv valve changed and also have new spark plugs. The old spark plugs where black. The next part that we are changing is the fuel pressure regulator because we just noticed fuel is leaking out of the top when the hose is taken off of the top. Could the fuel pressure regulator be the cause of my car problems.
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Wednesday, January 20th, 2021 AT 5:35 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
Ye, if the fuel pressure regulator is leaking, it would not hold fuel pressure and that would result in difficult starting.

Try turning the ignition on and off 2 or 3 times before attempting to start and see if there are any changes.
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Wednesday, January 20th, 2021 AT 5:35 PM (Merged)
Tiny
CALLENRSUE
  • MEMBER
  • 19 POSTS
  • 2003 CHEVROLET IMPALA
  • 85,000 MILES
I have a.2003 impala 3.4 with a stalling issue it only flags a P0101 code. I have replaced the Maf the Map the convertor and it still comes back I have checked the wiring tightened all the pin connections and check the voltage at the Maf it takes about 40 minuties before it stalls and normal freeze frame data shows a LT fuel trim at 135 but when it is running good LT fuel trim is -30 at idle out of idea's? Help
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Wednesday, January 20th, 2021 AT 5:36 PM (Merged)
Tiny
CALLENRSUE
  • MEMBER
  • 19 POSTS
Recleaned IAC and replaced still the same results. P0101? And stalls while just idling. Tps checks out 50psi of fuel pressure regulator is working holds vaccum. Swaped out MAF with a different Maf still same results.
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Wednesday, January 20th, 2021 AT 5:36 PM (Merged)
Tiny
MIKEDEROUIN88
  • MEMBER
  • 137 POSTS
.2psi of back pressure is too much but un related. Did u try a new gas cap? And also check the canister by the gas tank
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Wednesday, January 20th, 2021 AT 5:36 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,815 POSTS
Check for any of the following conditions:

a) An incorrectly routed harness. Inspect the MAF sensor harness to verify that the harness is not routed too close to the secondary ignition wires or coils, solenoids, relays or motors.

B) A low minimum air rate through the sensor bore may cause this DTC to set at idle or during deceleration. Inspect for any deposits on the throttle plate or in the throttle bore and any vacuum leaks downstream of the MAF sensor.

C) Inspect for any contamination or debris on the sensing elements of the MAF sensor.

D) Inspect the air induction system for any water intrusion. Any water that reaches the MAF sensor will skew the sensor and may cause this DTC to set.

E) A wide open throttle acceleration from a stop should cause the MAF sensor parameter on the scan tool to increase rapidly. This increase should be from 3-10 g/s at idle to 150 g/s or more at the time of the 1-2 shift. If the increase is not observed, inspect for a restriction in the induction system or the exhaust system.

F) A skewed or stuck TP sensor.

G) A skewed or stuck ECT sensor.

H) The barometric pressure used in calculate the predicted mass air flow value is initially based on the MAP sensor at key ON. When the engine is running the MAP sensor value is continually updated near Wide Open Throttle (WOT). A skewed MAP sensor will cause the calculated mass air flow value to be inaccurate and may result in a no start condition. The value shown for the MAP sensor display varies with the altitude. With the ignition switch in RUN position
and the engine OFF, 101 kPa is the approximate value near sea level. This value will decrease by approximately 3 kPa for every 1000 feet 305 meters) of altitude.

I) High resistance on the ground circuit of the MAP sensor can cause this DTC to set.

J) Any loss of vacuum to the MAP sensor can cause this DTC to set.

K) High resistance on the ground circuit of the ECT sensor can cause this DTC to set.

Problem could also be caused by aftermarket accessories.
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Wednesday, January 20th, 2021 AT 5:36 PM (Merged)
Tiny
KIM LETSHAVEFUN PERSON
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET IMPALA
  • V8
  • AUTOMATIC
  • 191 MILES
Car wont stay started once I take my foot off pedal.
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Wednesday, January 20th, 2021 AT 5:36 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,468 POSTS
Hello,

This is common when the throttle actuator needs to be serviced. here are two guides to help you fix the problem:

https://www.2carpros.com/articles/throttle-actuator-service

and

https://www.2carpros.com/articles/stall-at-idle

Please run down these guides and report back.
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Wednesday, January 20th, 2021 AT 5:36 PM (Merged)
Tiny
ERNESTADIEZE
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET IMPALA
  • 3.4L
  • 6 CYL
  • AUTOMATIC
  • 130,000 MILES
Good day guys,
Please I am finding it difficult to use the car. The engine will start then go off after three to four seconds. Called in a mechanic and he said the fuel pressure is low. After troubleshooting, he came up with the conclusion that the fuel pump is faulty and needed to be replaced. After replacement we are still back where we started.
At first the security light was on then with the help of some YouTube videos, I was able to reset it.
Now I do not have a security problem, but the car still will not hold steam.
Kindly assist.
I believe you guys can help me.
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Wednesday, January 20th, 2021 AT 5:36 PM (Merged)
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 42,468 POSTS
Hello,

This sounds like you have a crankshaft angle sensor that is going bad, When the engine stalls can you check it for spark, please follow this guide

https://www.2carpros.com/articles/how-to-test-an-ignition-system

and

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

Please let me know if you need anything else to get the problem fixed.

Best, Ken
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Wednesday, January 20th, 2021 AT 5:36 PM (Merged)
Tiny
WANDA L STEVENS-SMALLWOOD
  • MEMBER
  • 1 POST
  • 2003 CHEVROLET IMPALA
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 155,000 MILES
Will crank, but will not idle unless foot is on gas. There is no check engine light on. Had auto zone to check the obc showed no codes. Does not do it all the time. Sometimes I can crank it and it will run fine no problems other times cant not get it to idle. Notice that after putting in gas It will crank but not idle. Then after about ten times of stalling it will stop doing it.
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Wednesday, January 20th, 2021 AT 5:36 PM (Merged)

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