Fillister is just the shape of the head and has nothing to do with your problem. Fillister just means it is flat on the sides and flat or just slightly rounded on the top. The matter at hand is what kind of driver does it need. And I think you are correct that it is Torx. I have one of those folding sets, like allen wrenches. That kind of set would probably work for you.

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1998 C230 330,000 miles (currently dead of second failed EIS, yours will fail too, turning you into the dealer's personal human cash machine)
1988 F150 144,000 miles (leaks all the colors of the rainbow)
Previous stars: 1981 Brava 210,000 miles, 1978 128 150,000 miles, 1977 B200 Van 175,000 miles, 1972 Vega (great, if rusty, car), 1972 Celica, 1986.5 Supra