This vehicle has erratic idle speed?

I have seen a bad TPS sensor, or a vacuum leak that can cause this problem, do you have a check engine light on? We should run the codes; this guide can help:

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

If no codes are present, then I would clean the throttle bore and IAC motor (#4) here is the location and a guide to help as well:

Check out the images (below). Please let us know what happens.

erratic idle. In reply about the Dodge Dakota, it has had three new IAC Values in the last 20 months. They work for a while then it returns to the erratic idle. There is no check engine light on, nor has there been one come on anytime while this erratic idle is going on. Knowing these two points, do you have any more ideas on what I should check out?

In reply about the Dodge Dakota, it has had three new IAC Values in the last 20 months. They work for a while then it returns to the erratic idle. There is no check engine light on, nor has there been one come on anytime while this erratic idle is going on. Knowing these two points, do you have any more ideas on what I should check out?

Hi,

An erratic idle can be caused by a few different things. For example, the IAC (which you have replaced), an engine vacuum leak, fuel pressure, or the need for a tune-up. I'm sure there are other causes, but I would think these are the most common.

When you installed the new IAC, did you confirm the air passage was clear and carbon-free? If not, check that.

Here is a link that explains how to service the IAC:

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

If that doesn't help, I would be checking for engine vacuum leaks.

Here is a link that explains how to check:

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

Try these and let us know the results.

Take care,

Joe