Thanks to al of you for covering this topic.
I'm hoping this solves my low-power, poor mileage, odd bogging-down problems.
Seafoam seems to briefly make things better, but the issue keeps returning.
I just ordered two filters from here:
http://parts.olathetoyota.com/2003toyot ... parts.html
For my '03 GT 2ZZ.
part# ...ha! it doesn' have a part# on the webist, just this description: "Mechanical Catalog - 2003 - Toyota - MATRIX
engine, camshaft & timing, variable valve timing, filter Matrix No.2 1.8L, W/HIGH OUTPUT "
cost: $5.45
If you go to the 2003 Matrix XRS section there is a great pats breakdown diagram showing the two filter, item#32, and where they are. They are both listed as the same part number. I hope that is correct before I tear mine out on Saturday.
Vibe GT '03, Lava Red 2-tone, 16" wheels, Moon'n'Tunes, Injen CAI, ACT clutch, vented rotors, Tein coil- overs, Grafxwerks decals, lead foot on the gas and white-knuckled fist on the stick & Hankook RS-3 for AutoX
http://noraracing.net/