One problem related to loud engine noise has been reported for the 2001 Toyota 4Runner. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2001 Toyota 4Runner based on all problems reported for the 2001 4Runner.
[xxx] just driving along a loud noise was followed by excessive vibration and a connecting rod became disconnected from the crankshaft for no explainable reason, no crash occurred but easily could have as the oil pan was punctured and oil spilled out on the highway. I have discovered five out of warranty cases identical to mine in 5vz-fe engines where just driving along a loud noise was followed by excessive vibration and a connecting rod became disconnected from the crankshaft for no explainable reason and in each case no other service issue was identified: 1999 4runner, failed at 78,000 miles in 2003 1999 4runner, failed at 98,000 miles in 2006 2000 4runner, failed at 78,000 miles in 2006 2001 4runner, failed at 103,000 miles in 2008 2001 tacoma, failed at 92,000 miles in 2007. Information redacted pursuant to the freedom of information act (foia), 5 u. S. C. 552(b)(6).