carbon monoxide
While the vehicle is idling in park with parking brake applied, have someone block the exhaust pipe with a folded up rag. Any exhaust leaks will be easy to find, you'll hear them.
The most likely cause is an exhaust leak or a cracked exhaust manifold. While it is also possible that there is a problem with the Camry's catalytic converter, check to see if there are any leaks from the exhaust or any problems with the muffler first.
check your engine for a cracked manifold (covering of the engine parts and cylinders. also look for any exhaust leaks. it sounds like the exhaust noise isn't making it to the muffler as it should and instead is coming from the engine directly.
There's a good chance it's welded on. That means cutting the muffler off. Your best bet is to have a pro muffler shop do the work. It's not worth messing around with possible asphyxiation, particularly in the winter when we might be stuck in the snow and ice and need to run the car for heat. Exhaust leaks into the cabin are a bad thing ~
because you touch yourself at night
You can smell exhaust because your exhaust pipes and exhaust system has worn out. As a result, the exhaust and carbon monoxide it contains leaks inside the van. Soon, it will not be a problem because the carbon monoxide will have killed all of you.
Seems the flexpipe leaks at the ends...
Bad head gasket or... Crack in exhaust port in head. Check exhaust for presence of antifreeze smell or exhaust gas in radiator.
First off, crawl under the truck and see if your present muffler is welded on or clamped on. If it's welded on you will need to get an exhaust cutting tool from like Autozone and cut the old muffler off BUT before you do, get your new muffler and measure how far the inlet neck is and outlet neck is on the new muffler and this will tell you how far to cut. You could hold the new muffler up to the exhasut and mark how far from the muffler you need to cut. This is assumign you are replacing the bad muffler with a new one of the same size. Now there is an inlet pipe and and out let pipe on the muffler. You will also need to have the right size clamps. Pu tone clamp on the exhaust pipe going to the engine, then push the exhaust pipe into the inlet end of the muffler and slide the clamp down and snug it up but do not tighten it. Put the other clamp on the exhaust pipe towrd the rear of the truck, push the exhasut ipe into the outlet end of the muffler and then slide the clamp down onto the joint and snug up. if everythign aligns right, then tighten the clamps. Sometimes if you overtighten the clamps you will have exhaust leaks. If you cannot get the joints to seal, you may need to get your system welded. If you exhaust is leak free then you are done. After a few hot and cold cycles you may just want to crawl back under and check the bolts on the clamps just in case they came loose from the heat and cold cycles.
I think what you are seeing is your muffler leaking condensation from a weep hole. This normal and will stop after your vehicle has reached full operating temperature.
Most connections / joints between parts have a gasket to prevent leaks. So a failed gasket is a typical cause of leaks, including where the exhaust pipes connects to the exhaust manifold.
The rattle might be a loose heat shield but the loud exhaust can only be a hole somewhere. start at the manifold an work your way back listening and feeling for leaks.