My engine stalls at idle ?

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

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?

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

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

Car shuts down when in gear.

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

I replaced the spark plugs, I replace the wires, I replace the three coils and it still will not stay running.

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?

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

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.

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.

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

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.

.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

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.

Car wont stay started once i take my foot off pedal.

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.

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.

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

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.

Hello,

Two things come to mind, the first is it could have a vacuum leak, here is a guide to help you confirm the problem.

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

If this seems okay the other would be that the throttle bore and IAC if it has one needs to be cleaned.

Here is the guide for that as well.

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

Please let us know what happens.

Cheers, Ken

I think I have a big problem with my car, my car ran fine smooth and then the AC went out, so I refilled with the r-134a since I needed to take the car to the emissions test, I also filled the gas tank and added a fuel injector cleaner. For some reason the computer at the emissions test facility could not read my car computer, and I was told to go back in a week. The next day I turned my car and on my way to the store it just died, I then would turn it back on and with in 2-3 seconds it would just died. I managed to get my car to my uncles (old school mechanic) by turning the car on and putting pressure on the gas pedal if the RPM was below 800 the car would just shut off. the codes are P1122, P0122, P0140 & P0141. We changed the crank relay sensor, the TP sensor the gas pressure it's in between 40-50. at this time i have no idea on what's wrong with it. any help would be greatly appreciated.
If I get a possible solution I'll post once it's solved and will make a donation to this site.

Thanks.

Lets try the idle air control valve

Disconnect the air intake ductwork from the throttle body.

Start the engine, then increase and hold the idle speed to 1,000 to 1,500 rpm.

Spray the throttle cleaner or engine cleaner into the throat of the throttle body, aiming for the idle air bypass port (usually located on the side or top of the throttle body opening). Give this area a good dose of cleaner (about 10 second's worth).

Turn the engine off to allow the cleaner to soak into the IAC passageway.

Wait about three minutes.

Restart the engine, rev and hold at 1,000 to 1,500 rpm, and repeat the cleaning process again.

Turn the engine off again, and reattach the air intake ductwork to the throttle body.

Start the engine and rev and hold to 1,500 to 2,000 rpm until no white smoke is coming out of the exhaust pipe.

If this fails to make any difference, you can remove the IAC valve from the throttle body and spray cleaner directly on the tip of the valve and/or into the ports in the throttle body. Let the cleaner soak awhile, repeat as needed, then reinstall the IAC valve, start the engine and run it at 1,500 to 2,000 rpm as before until no white smoke is seen in the exahust.

If the idle speed still surges after this, the IAC valve is defective and needs to be replaced.

Thank you very much for the feedback, in the en it ended being the mass air flow sensor that needed to be replaced. the car now starts fine and rides smooth, but after clearing the codes and 1-2 days after the check engine light come on, and the code P0141 comes out on the scanner, I had a new 02 sensor on hand (brand new) and replaced thinking this would solve the problem but it didn't. The check engine comes on and the same code P0141, what's next or what other sign I should look for?

Thanks!

A code P0141 may mean that one or more of the following has happened:

open or short to ground in the wiring harness
O2 heater circuit wiring high resistance
O2 heater element resistance is high
Internal short or open in the heater element

Possible Solutions Replace oxygen sensor (cannot repair open or short that occurs internally to sensor)
Repair short or open or high resistance in wiring harness or harness connectors

Since I replaced the O2 sensor with a new one on sunday, Should I just check the wires to make sure they are ok? the O2 that I put in was a OEM right out of the box, how about the fuse/relay?

Thanks for the quick reply.

Check and test the wires and connection

My Impala starts then dies as soon as I put my foot on brakes to put it in gear

Yesterday we replaced the O2 Sensor again and cleared the codes, check the wires and there is voltage, I ran the car for about 30 min on the highway with the scan tool attached to it, it ran fine the only thing I noticed was that the O2 heater check (I think), and the EGR thing were incomplete, my guess was to run it more so that the computer would reset completely. This morning I decided to ride to work with the scan tool attached everything seems fine except for the O2 heater thing and the EGR, once parked i decided to scan the vehicle once more and it gave me these two codes P0140 and P0141. P0140 I noticed it said intermittent and the P0141 was pending. i'm really going WTF?? I know it's hard to detect the problem directly, but what should I do next? is the O2 sensor atfer the cat bad or can the cat be bad?

You may have a vacuum leak from the brake booster, to check, remove and block booster vacuum hose at the booster, start and apply brakes, if engine does not falter, you will have a booster problem, do not drive with booster disconnected and brake will be very heavy and stopping power will be poor.

You may have a bad catalytic converter, especially if you never replaced it.
Check for backpressure.
You can also check the difference in temperature between the converter inlet and outlet.

"P0140 I noticed it said intermittent and the P0141 was pending. i'm really going WTF?? I know it's hard to detect the problem directly, but what should I do next? is the O2 sensor atfer the cat bad or can the cat be bad?"

What o2 sensor are you replacing. both these codes are related to the rear o2 sensor "post cat converter".

Replace the o2 sensor after the cat converter