Recently tried to replace my IACV with an aftermarket one to see if it would help with my car surging during idle and it ended up giving me an even worse surging issue once installed. Car would originally surge from around 1200-1500 RPM during idle, but with the new IACV installed it was surging from 1500-3000 RPM during idle. Took it off and compared it to the original IACV installed on my car and noticed that the valve on the new part seemed to rattle when shaken whereas there was no rattling at all on my older one. Ended up trying to clean out my original IACV with some brake cleaner and reinstalling it and it seems a little better but still fluctuates a little bit. Is it normal for IACVs to rattle when shaken or did I just get a dead part. Is there any way to tell for sure if the idling issue is being caused by the IACV or if it could be something else? I have tried disconnecting the IACV connector while the engine is running and it seemed to go down in RPM but stay steady, which made me think it was an IACV issue in the first place.

 

Try another one, sometimes you can get a bad one or the incorrect one. Make sure the gasket is new on the IACV,

You can also run some test to see if you have a vacuum leak which will cause the idle to surge.

 

I’m going through the same thing. Replaced with another valve and it got worst. Any update?

 

check for vacuum leaks somewhere in the lines leading to the manifold. Also, try resetting the ecu also so its on a fresh learn cycle when it starts.