Some Chevrolet Trailblazer owners report experiencing rough idle and severe vibration when stopped in drive, which may be attributed to several factors. These owners often suspect issues with motor mounts, as the symptoms are consistent with potential motor mount failures. Additionally, a vacuum leak is commonly identified as a cause of rough idling in these vehicles. Problems with engine components, such as VVT solenoids or fuel injectors, can also contribute to the vibrations and rough idle, particularly noticeable at 650-700 rpm when the vehicle is in gear. Some owners have found that the rough idle worsens when the AC is activated. It is recommended to inspect motor mounts, check for vacuum leaks, and ensure overall engine mechanical soundness, as even non-visible damage to motor mounts can lead to significant issues. Furthermore, checking for stored trouble codes can help diagnose the underlying problems. Some users have noted that dealerships may initially overlook these issues, emphasizing the need for thorough diagnostics. Regular maintenance and prompt attention to warning signs are crucial for preventing these concerns in the future.