Toyota 4Runner low idle and engine rumbling noise with bad vibration at startup on Toyota 4Runner

Some Toyota 4Runner owners report experiencing issues such as low idle, engine rumbling noise, and bad vibrations at startup. These problems may stem from bad engine mounts, which can lead to noticeable vibrations and noise, particularly during startup. Additionally, mechanical issues like engine timing problems, low compression in cylinders, exhaust leaks, worn piston rings, or the presence of metal shavings in the oil can contribute to rough idling. Common causes of rough idle in the 4Runner include vacuum leaks and spark plug issues. Furthermore, a faulty idler gear on the timing chain can also result in vibrations and noise, potentially requiring replacement under warranty. Low oil levels are another factor that can exacerbate engine noise and vibrations, and while adding oil may provide a temporary fix, it is crucial to address the underlying issue. Owners experiencing these symptoms should seek inspection from a qualified mechanic for accurate diagnosis and resolution.