Hi. I have a 2007 V6 with 177,000 miles, and just recently I've been hearing what very much sounds like any normal exhaust leak, which seems to be coming from near the front of the car. It's hard to tell because it only happens when I'm driving so I can't crawl under the car or get under the hood, and it comes immediately and then fades out eventually. It's quite loud at first. I don't hear any hint of a leak before or after this happens. It can last anywhere from 30 seconds to several minutes, and it's never happened at startup or soon after. I guess it could be something else but I've been driving for 30+ years and it sounds like an exhaust leak. The check engine light also is not on. I haven't yet taken it in for service. Any help on this would be much appreciated. Thanks.