I'm pretty sure it has just a muffler, it looks the same as some I've changed before. Most of the time if it has a cat there is also a muffler right after. I'm gonna bring a tank from home and try a different fuel source and if that doesn't change it I'll try a tune up again just to be sure. Tune ups fairly cheap. I did look at the plugs and they look good, but the gap did look a little big(46 th) I'm not sure what it should be. Thanks for your help and I will let you know how it goes tomorrow.