DETROIT—Engineers behind the Chevrolet Corvette, Cadillac CTS, GMC Sierra and Buick Enclave are learning on dealership sales floors and in service bays what customers like and dislike about the cars and trucks they helped create.

Have you ever ordered a meal that sounded delicious on the menu, but tasted terrible once it arrived at your table? Have you ever purchased the latest recording from your favorite musician only to find it lacking? No matter what the product or service, what you expect isn’t always what’s delivered.