I was driving in to work today, and about 4-5 miles before I got here. I noticed a very loud rattle. As the RPM's went up the rattle sped up, as well got louder. If I took my foot off the gas and coasted it would almost go away. Where should I start looking? How much should I be expecting this to cost? I've read through quite a few posts here and seem to think it could either be the harmonic balancer, or the timing belt. Either of which won't be to easy to get looked at, and fixed. I appreciate any help you give me! God Bless!