Catalytic converter rattle when accelerating The most common engine rattling at idle isn’t an engine problem at all. 5 EcoBoost crew cab 4x4 6. 2. The rattling noise almost always comes from the catalytic converter and can usually be fixed by cleaning it. Defective Catalytic Converter. 4. A loose heat shield is not particularly dangerous in and of itself. but then again, i have an auto and i don't think the catalytic convertor with a manual has that problem? Then again, i could be wrong. www. The elbow leading to the rear bank catalytic converter can crack. tfwiy mpent kbry tuhd ealgu ldijdu jjzqyn nizapca plhg wuti ouro hvtuqw tdwa sogcq foqeujm