DETROIT – Car buyers looking to purchase a ’12 Kia Rio or Soul with stop/start will have to wait a little longer, as Kia delays the fuel-sipping technology’s introduction until the second quarter.

“It is a new technology, (and) we want to make sure it’s giving consumers the experience they would expect,” Michael Sprague, vice president-marketing for Kia Motors America, tells WardsAuto in an interview.

Sprague says feedback from media members who have driven stop/start-equipped Rios and Souls compelled Kia engineers to “tweak” the technology, which the auto maker calls ISG, for Idle, Stop and Go. The Kia executive does not elaborate.

Some reviewers have complained of a noticeable shock, common to many vehicles with stop/start systems, when the car’s engine automatically shuts down at idle and then restarts.

Sprague says the sales delay also allows Kia to further train its dealers so they can better explain the technology to customers.

Kia plans to call attention to stop/start in Rio and Soul marketing campaigns. But Sprague says the auto maker likely will direct consumers to a website video, rather than trying to describe the technology in a commercial.

Kia’s ISG functions under most conditions, although extreme cold or hot weather may prevent it from activating, the auto maker has said.

Stop/start systems save fuel that otherwise would be lost during engine idle. The technology is gaining popularity in the U.S. after sweeping Europe, where gas prices hover near $10 a gallon.

Ford recently announced stop/start availability in its redesigned ’13 Fusion. Luxury brands BMW, Mercedes-Benz and Porsche also offer the technology in some U.S. models.

The next-generation Rio subcompact has been on sale since last fall without the gas-sipping ISG, as has the refreshed Soul compact.

Soul sales soared in 2011, exceeding 100,000 units for the first time in a calendar year. But Rio deliveries tumbled 18.3% compared with the prior-year to 20,111, according to WardsAuto data.

Sprague blames the Rio’s decline on lack of dealer inventory. Previous-generation models sold out about June, he says, adding hatchback output began in September.

“We didn’t start production of the sedan until November. So (we’re) just filling the pipeline.”

However, December was a good month for the car, with Rio sales spiking 128.3%, although a 28 days’ supply was below the segment’s industry average of 54 for the month, WardsAuto data shows.

cschweinsberg@wardsauto.com