well i was wondering if any one else here has the same thing happen to them.. i got a 9 mr with a tune and when ever im idling and another car with a loud exhaust drives by me it some how causes my car to drop idle about 300-400 rpms almost feels like it will stall but dosent.. well its no big deal cuz it dosent stall but i jus wanted to see if that happened to n e one else and if they knew y it happened

 

It will do that when you drop the hood too. I believe the knock sensor causes that... Someone else with have to explain though...

 

It probably disrupts the MAF signal.

 

I have been told it's the maf that causes this, I thought it was the knock sensor but I think all evos do it don't worry it's normal.

 

Let's see if I can explain this correctly...

The MAF measures the frequency of the air passing through it. A loud noise will disrupt the frequency, making it look like the airflow increased. The car adjusts by adding more fuel, causing a drop in idle. I think open element intakes are more susceptible to this.

My car does this too. I was staging behind a very loud Honda last Sunday and every time he revved, my idle dropped. My friends think it is hilarious.

 

nice well that makes sence with the MAF theory and also my friends thought it was pretty funny also when his wrx would make my car do that lol