Could this be the novella City of Truth by James Morrow?

Truth reigns supreme in the city-state of Veritas. Not even politicians lie, and weirdly frank notices abound—such as warning: this elevator maintained by people who hate their jobs: ride at your own risk. In this dystopia of mandatory candor, every preadolescent citizen is ruthlessly conditioned, through a Skinnerian ordeal called a “brainburn,” to speak truthfully under all circumstances.

This review mentions the 'Ford Adequate'

I read this back when it came out, and had to see if it holds up (spoiler: it does). The story is unimportant: what you come for here is the setting, a city where people are conditioned (ala B F Skinner) to tell the truth. Instead of a Ford Reliant you have a Ford Adequate, and so forth. Lots of fun. Four figuratively pointed and bright objects.

This is the novella City of Truth by James Morrow.

Truth reigns supreme in the city-state of Veritas. Not even politicians lie, and weirdly frank notices abound—such as warning: this elevator maintained by people who hate their jobs: ride at your own risk. In this dystopia of mandatory candor, every preadolescent citizen is ruthlessly conditioned, through a Skinnerian ordeal called a “brainburn,” to speak truthfully under all circumstances.

This review mentions the 'Ford Adequate'

I read this back when it came out, and had to see if it holds up (spoiler: it does). The story is unimportant: what you come for here is the setting, a city where people are conditioned (ala B F Skinner) to tell the truth. Instead of a Ford Reliant you have a Ford Adequate, and so forth. Lots of fun. Four figuratively pointed and bright objects.