Some Cadillac ATS owners report experiencing issues such as misfiring and coolant leaks, particularly in the 2013-2014 models with the 2.0t engine. Others have encountered electrical failures attributed to a bad battery. Additionally, some owners notice engine vibration, pulsation, or shaking, along with transmission shuddering. There are also reports of piston cracking leading to significant engine failures and turbocharger failures that result in poor performance and costly repairs. Excessive oil consumption has been noted, which can contribute to engine wear, and coolant leaks can lead to overheating and potential engine damage. It is crucial for owners to be vigilant about these problems and conduct thorough inspections to maintain the reliability and performance of their Cadillac ATS. Regular maintenance and prompt resolution of any issues are recommended to prevent further complications.