My 98 Camry is producing some engine noise. On initial startup (after 24 hours) when the engine runs slightly higher than 1,000 rpm, there is a metal ringing noise that sounds like something is loose. When it's all warmed up and running under 1,000 rpm it just sounds a bit rough. This was present before I had it serviced by Toyota, and they didn't seem to find anything abnormal about the engine (maybe I need to tell them what to look for <_< ). So I have a rough and ringing engine. It runs just fine while driving, quiet and smooth. P.S. My engine is the 4cyl