A sluggish engine and slow acceleration definitely sound like the catalytic converter. Luckily, the catalytic converter on your Kia is covered by the vehicle’s emissions warranty. Kia’s Emission Warranty offers coverage on all related parts for 24 months or 24,000 miles, whichever comes first, and covers specific parts for 96 months or 80,000 miles.
Along with other emission control devices, federal law requires all automotive manufacturers to replace a defective converter for up to 15 years or 150,000 miles, whichever comes first. But because this coverage varies by state and vehicle type, check your owner’s manual or contact your local Kia dealer for your warranty information.