Since a month ago, I sometimes hear this popping sound underneath my car in the middle section. But I hear it every 10 seconds when the car is still and my windows down, and its a single popping noise. Could it be coming from my custom exhaust?

 

Do you still have a cat? If so, its just expanding contracting. Dont worry about it. (Assuming you also hear this noise when the car is off, and hot) It can also be the oxygen pump for the car....if its a single popping noise....if you hear a few in a row, its the expanding/contracting. Either way, its normal.

Also, remember, its an s2000. Youll hear noises all the time, dont panic.

 

whew! ok thanks. and yah I still have my cat on

 

Its just your exhaust dont worry about it mine did it all the time.

 

https://www.s2ki.com/forums/index.ph...&f=22&t=441122