toyota has a kit part#00602-17802-003 that will fix this problem, i have seen a good photo, and it looks like something i did for mine.
03 toyota matrix XRS 6 speed, lunar mist,factory 17 inch rims w/firehawks- summer tiresfactory 16 inch rims with dunlops- winter tirestrd sway bars, trd strut brace, trd sport muffler,trd quick shifter,trd cold air intake, toyota tundra dual horns,factory toyota wing from toyota canada, both front door handle modsNEW pioneer AVIC-D1 nav unit, XM radio installed
If I remember correctly, the kit wont actually stop the clicking. It'll only make it less noticeable and muffle it by fastening the "TRD" vsv bracket to the engine compartment with a couple rubber insulators. The rubber keeps the clicking from transferring to the metal compartment paneling, thus making it quieter.I think the kit cost more than $30 US and IMO isn't worth the money. You can easily make your own with a $0.85 "L" bracket and a couple $0.30 rubber insulators. Or you can always zip tie the vsv to a free hanging hose or wire harness. Either method will quiet it down as much as the TRD kit.