2004 Kia Spectra Q&A
2004 Kia Spectra Question: What causes hard shifting in low range to mid range?
You probably have a plugging and failing cat. converter or bad o2 sensor for the p0420 error. The p0455 error is either a loose gas cap that needs replaced or a leak in the evap system. Look for cracked or loose hoses or vacuum noise or fuel smell in the system. - csubak30