Have a Civic Ex and about a week ago I was in a rush and I was driving pretty fast and after that I started noticing this rattling noise it sounds like its coming from below the car in the front somewhere. I only really hear it when I stomp it or around 3000 rpm. I just had the resonator cut off and a new cat back muffler put on but I dont know if that has anything to do with it. I was wondering if it could be the catalytic converter cause this car came from up north so the cat is really rusty. Thanks
It's probably something(loose) in the exhaust system either internal or external that triggers at rpm or load. Could be as simple as a loose heat shield. Could be a clamp let loose? Best thing to do might be to raise and get under while ya rev it?