Austin6539 West Hwy 290Torn down for a highway widening project c. 2004 that has yet to happen. A large tree called the Taco Bell Tree was here and later moved.
7015 Burnet Roadnow Northcross Motors, also A Cut Above Motors before
Bryan2423 Blinn Blvd.Inside student center, existed briefly in the late 1990s and early 2000s. Now a generic branded option (that does not sell tacos)
920 S. Texas Avenue#2310, closed a number of years ago (late 1990s/early 2000s), now Frittella Italian Café
Denton917 Sunset St.#2020, Built 1980, later "Japango" and now I Love Sushi (stylized with a heart)
Fort Worth1405 Cherry LaneClosed relatively recently
Houston8800 W. Sam Houston Pkwy. SInside Auchan, though it appeared to close before 2003
1803 W 43rd St.#1010, sold 1996, currently a Prudential Office
9066 Long Point Rd.#957, sold 1987, currently Auto Concepts
7703 Long Point Rd.#999, built 1972, currently El Guero Check Cashing
8101 FondrenNow A-1 Dental.
5210 Bissonnet St.#142, sold 1994, currently Roadster Grill
6523 Westheimer Rd.#238, torn down for a strip mall
330 S 69th St.#313, looks like former restaurant was built into larger building, or maybe just torn down - not sure about this one, can't really figure out where this should be unless it's actually Wayside Dr.)
5801 KirbyNow Starbucks Coffee. Closed sometime in the late 1990s (not 1980s)
370 Uvalde RoadClosed and demolished around 2014
Jersey Village16009 Northwest FreewayTorn down for rebuilding the US-290/Beltway 8 interchange (closed 2012, razed 2013)
Waco1725 North Valley Mills DriveMoved to 1515 North Valley Mills Drive in mid-2000s, currently Spiciness Mexican Grill

Thank you to "Sevfiv" for finding old 1970s ones in Houston no longer in existence (plus Denton and one in Austin), the Fondren location was stumbled upon in newspaper articles.