Hyundai elantra 2001 help pls!!!
I own a Hyundai elantra 2001, the check engine light is on for the longest time and we got around to replacing both oxygen sensor which fixed the problem. The check engine light turned off for a while but it came back on, now the fuel efficiency is low and putting the car into neutral gear or starting it makes the rpm skyrocket to 2k and hovers at that point for a couple of seconds. I don't know what could be wrong but my guess would be that the catalyzer converter is getting old, has anyone had the same problem? Please help.