u/Outrageous_Joke2608

I suddenly heard this knocking sound coming inside the cabin. I have a AA catted GESI Downpipe and everything else is stock. Have had the DP installed for around two weeks now and had no issues. Didn’t even drive that hard today and suddenly it start making this knocking noise once I came home. Engine seems to be fine I checked. Opened the front hood and didn’t hear any knocking noises. In the outside also I can hear this sound. I seem to be able to only hear it when I’m inside the cabin.