While the Toyota 4Runner is generally regarded as a reliable and durable SUV, there are a few model years that stand out for potential issues. One such year is the 2003 4Runner, known for transmission problems that could lead to costly repairs. Another model year to approach with caution is 2010, primarily due to reported issues with the automatic transmission and sunroof leaks. Additionally, some owners have experienced premature wear on suspension components in the 2010 model. It's also advisable to be cautious with the 2016 4Runner, as there have been complaints about the Entune infotainment system malfunctioning and electrical problems surfacing. While these issues aren't universal across all vehicles, prospective buyers may want to consider them when evaluating used Toyota 4Runners from these particular years.