If you still think you may have an exhaust leak you could try a drop or two of liquid dish soap in a squirt bottle full of water. Spray the connections (when cold of course), start her up and look for bubbles.
Looks like you're in Arizona. I live south of Chandler, if you need a hand with filter install let me know, I did it a few months back. Bad news is, I'm in California this weekend, back on Tuesday.