I just got my magnaflow muffler installed in my 2001 Montero Sport. 2.25" from the muffler exit to a nice chrome tip. I had the shop do a side exit right behind the passenger rear mudflap. I noticed a burning smell, sort of like plastic. I popped the hood while the engine was running and sniffed around. no smell. I go by the tailpipe and it's coming out of the exhaust! Because of the side exit, when the windows rolled down and you're at a stop, it gets into the cabin. What can it be?