Car surging up and down on idle when in reverse and stopped

Hi,

If the IAC is new, the next thing I would suggest is to check for engine vacuum leaks. Here is a link that shows how that is done:

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

Also, if the check engine light is on, have the computer scanned for diagnostic trouble codes. Here is a quick video showing how that is done:

https://youtu.be/b2IJGfImVvw

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I realize most people don't own a scan tool, but oftentimes a parts store will do it free of charge.

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

Take care and God Bless,

Joe

I have checked for vacuum leaks haven't found any. The obd2 plug for the scanner isn't hooked up in my car at least that's what auto parts store said when they tried to hook scanner up. But I have tried looking for vacuum leaks and new IACV valve and new map sensor just because. Any other ideas? Also when im driving on highway and step on gas the RPMs climb but my MPHs climb very slow, like it's the torque converter or something possibly? It's an automatic.

Hi,

It sounds like the transmission is slipping. However, I need you to start a new thread on that topic. We try to keep them specific to one so it helps others. I hope you understand.
Just copy and paste it.

https://www.2carpros.com/questions/new

Did you check for the data link connector? I attached a pic below showing the location.

Check to see if it there and if there are wires attached to the rear of it.

Also, when you replaced the IAC, did you check to make sure there wasn't excessive dirt or carbon in the throttle body? Here is a link that shows how to service one:

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

Let me know.
Joe

Hi TYSON BROWN,

This sounds like you have multiple issues, every issue has to have a new topic started. Your connector is there you just have to look for it.I suggest reinstalling original idle motor(when at idle and park and still have issues with idle ) you have to scan vehicle (try another parts store) also when installing a idle speed motor you have to clean the intake side of the idle motor.
(carbon build up).

Let us know what happens and please upload pictures or videos of the problem.

Cheers, Nick

Sorry about that. Yes, i'm just having 2 issues that i'm stumped on. Okay, will try to upload video of it surging in reverse and idle up and down.

Please follow procedures first
follow my suggestion first
Cheers, Nick

Well, see I did take whole throttle body off and cleaned it before I installed new IACV valve, I did not like the common sense stuff, it has got to be something else failing. I don't think it's buildup anywear I try clean the throttle body every once in awhile and new air filter and things.

And it was doing this before I ever messed with anything, although it seems a little better but it still always surges in reveres and once in awhile at lights.

You are correct now the best is to scan and retrieve codes it will give us a idea what is going on (when in park and idle does the idle fluctuate?)

Yes, it fluctuates and revs high a little bit sometimes, it does it everytime in reverse heavy surge, but the auto parts store said they can't hook a scanner up because my obd2 thingy majig isn't hooked up.

I would go to another parts store, it is possible then connector has been push up and it is behind, and just can see it, you have to look for it.
Check out the diagrams (below).
Please run down these guides and report back.

Cheers, Nick