I searched the forum for other threads on this particular issue but I couldnt find any so please dont shoot me. I just installed some resonated test pipes on my g with stock exhaust. I noticed that when my car is in decel that it makes a rattling noise right around 2500 all the way down to about 1700. Do you know what this could be? Im pretty sure that its not rasp, but i dont know. Has anyone else seen this? Thanks a lot.

 

yes, it is rasp. just installed test pipes as well.. there is no drone at highway speed but upon heavy exceleration or deceleration you will get the test pipe rasp

 

well i know what the rasp sounds like. it isnt under heavy acceleration, it is just under deceleration. it is a quick pinging sound. i checked the bolts twice to make sure they are tight. i was woundering if it makes a sound seperate from the rasp that is typical for test pipes with flex joints?

 

It's normal. My friend has it installed too and he gets the exact same symptoms.

 

check your o2 sensors, pull them out and see them. mine was making noise with the decel on my testpipes.

they rubber malleted the testpipes gently and found the rattling is because of the o2 sensor on driver side. it was melted and warped so it caused the rattling... i wonder if anyone else had that problem?

The car place said the testpipes without the catalytic ceramic stuff is way too hot and direct on the o2 sensor, causing them to prematurely melt and fail. I ordered a stock one from dealership and hope it's gonna be ok. so far the passenger side one seems fine.

no wonder my gas milage was so bad!

 

same thing happened to me, exactly... Gas mileage doesnt improve much id have to say. part of having TP's!