Engine reduced RPMs to 400 while driving and shuts off?

Hi,

Have you checked to make sure there are no engine vacuum leaks? I realize the vacuum hoses are new, but there could be a leak at the intake. That can cause this type of issue. Also, fuel pressure can do it as well.

Start with checking for leaks.

Here is a link that explains how to do it:

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

Also, have the same codes returned since the work was done, and is the mileage you indicated accurate?

Let me know.

Joe

Thanks for your time.
Yes, every single vacuum hose I checked and renewed.
Is it okay to adjust the idling?
When I start the car and start driving.
No problem at all.
After driving 2 to 3 miles.
The RPMs are dropping down.

Correct me if I am wrong.
The new fuel injector might be giving this low RPMs.
Thank you again.

The issue is likely related to the idle air control valve (IAC). The IAC is what is responsible for maintaining engine idle speed.

The IAC is located on the throttle body and can be serviced.

Here is a link that explains how to service one:

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

If you service it, make sure the airway ports in the throttle body where it mounts are not carboned.

I attached the directions below for removing and replacing the part.

Let me know what you find or if you have other questions.

Take care,

Joe

See pics below.

Hello Joe,

Thanks for your advice.
I changed Air Contro Valve and cleaned the throttle body and the shutter.
Now it stopped hesitating when stop and go.
But still shutting off after every few minutes.

Hi,

Thanks for the update. It sounds like we are making progress.

Does it stall after a few minutes when it is at an idle? Is there anything you can do to prevent it from happening?

Let me know.

Take care,

Joe

Thanks for your time...
I am cleaning throttle body, shutter and renewed spark plug wires. I drove close to 85 miles without any problem when the car was in parking. It was idling close to 1,600 RPMs.
When I was driving it was not hesitating nor did it shut off.
Next morning when I started the car it started misfiring and didn't want to move, I checked the codes.
They were po120, po 505, po172, and po301.
I really don't understand I change fuel injectors spark plugs spark plug wires coil fuel filter fuel pump.
I went in manually to increase the RPMs to 1,500 and drive 4 to 5 miles. It was running okay. But, I am afraid to go for a long test drive.
Please tell me what and where I am making a mistake.
Or some type of Karma which is on my head not allowing me to do anything right.
Thank you all.

Hi,

The new codes seem related. See pics 1 and 2 below. The engine is running too rich which is likely the cause of the misfire and problems you are experiencing.

So, I have a few questions. First, are you located in CA? Also, have you checked the fuel pressure to make sure there isn't an issue with the regulator?

Next, have you done anything with the idle speed control valve? See pic 3. It is located on the throttle body.

Let me know.

Joe

See pics below.