Newbie with an exhaust leak on his '06 Yaris

[ToYarta]

Hi guys,

I have a red 2006 Toyota Yaris 3-Door (82,000 miles and going ) that's been more reliable than Old Faithful- save for an exhaust leak that has recently developed. The tall-tale "tappety-tappety" sound only makes itself heard at idle and low-RPM so it's not THAT irksome of a problem. I'd just rather resolve the issue before it starts to get on my nerves

So I began to investigate the precise source of this leak only to notice that the bolt attached to the exhaust manifold insulator was missing. Could this possibly cause an exhaust leak or does the problem most likely originate from a leaky exhaust manifold gasket? Refer to this diagram to see which bolt I'm talking about (ref # 91631):



Please note that this diagram belongs to toyotapartszone.com and is not mine