Running bad

Hi and thanks for using 2CarPros.

It sounds like the idle air control valve is bad. It is responsible for maintaining the engine idle speed. When they go bad, the engine idle will lope up and down and often times stall.

The component is located on the throttle body. I attached a picture.

Here is link that shows in general how one is replaced:

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

Here are the directions specific to your vehicle for replacement:

Removal
4.7L V-8

The Idle Air Control (IAC) motor (3) is located on the side of the throttle body.

1. Remove air resonator box at throttle body.

2. Disconnect electrical connector from IAC motor.

3. Remove two mounting bolts (screws).

4. Remove IAC motor from throttle body.

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Install

1. Install IAC motor to throttle body.

2. Install and tighten two mounting bolts (screws) to 7 Nm (60 in. lbs.) torque.

3. Install electrical connector.

4. Install air resonator to throttle body.

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Let me know if this helps.

Take care,
Joe

If the IAC was replaced and it still does the same thing, the next thing I would do is check for a vacuum leak. If unmetered air gets into the engine, it will cause problems, rough idle, stalling. Take a look through this link. It discusses how to check for a leak.

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

Let me know if this helps. Also, let me know if the check engine light is staying on when the engine is running. If it is, you need to scan the computer to identify diagnostic trouble codes. Here is a quick video showing how it is done:

https://youtu.be/YV3TRZwer8k

Let me know what you find.

Joe

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

Take care,
Joe