Exhaust Problems

I got a stock exhaust on my v6 stang. I recently started hearing a loud deep noise whenever I accelerate so I thought I had a hole in my muffler but when I looked underneath the car the muffler and tailpipe was just rusted but no holes. The sound is coming from just underneath the engine. Does anyone know any site where it shows pics of the under part of the car and does anyone have an idea where this sound might be coming from? I was told it could be from a hole in my H pipe or it could be my headers. Any advice on this would be helpful.

collector gasket?

What is a collector gasket and where is it located?

Friend of mine had a 2000 6-cyl with the same problem. It turned out to be a hole in the h-pipe, right side, from the A/C dripping on it. Avoid a dealer for repairs! They wanted to install a $700 kit with the catalytics included. All it needed was a new length of pipe welded into the spot for $75 and 20 minutes at a muffler shop.

Why not just take a mig welder and fill in the hole?

Personally, I wouldn't fill. Just get a little piece of sheet metal and patch it. If a hole rotted through it, you probably arent going to have much material surrounding it to work with. But it really depends on the size of the hole.. if its just a pinhole, say 1/4" diameter max, yeah you can fill it with weld.