I have Hundai Accent 2011 model with Automatic transmission,after traveling 10-20 kms when I change gear to neutral or park, the RPM rises to 3000 and doesn't come down. I took the car to the Hyundai service centre, they cleaned the carburetor with Delco spray and it was OK for few minutes, but after traveling 5 kms the RPM came back up to 3000 in neutral and park.
please suggest what could be the problem?
