I have had a ticking for the past year or so, at low speed crusing, 25 - 35 mph and 2000 rpm . I have discovered it is coming from the left side exhaust. I tightened the nuts and it went away but started again in less than an hour

. Next I replaced the gaskets, same results, though it took it a day to start ticking again

. I was wondering if there is anything that might help with this, sealing compounds or some trick to installing the gasckets? Oh yeah, 1999 IS with 45000 miles, stock exhaust with baffels removed. Thanks.
ps maybe an extra tech session for inzane??? See you there!!!