P0440 and P0456 EVAP Codes
4.7 liter with 106,300 miles. In addition to the codes and check engine light on, the RPM varies 200 - 600 RPM at all vehicle speeds. At idle it varies from about 500 - 1100 RPM and at 70 MPH it varies from 1800 - 2400 RPM. Any help or suggestions on where to start? And a place to get parts for the EVAP would be appreciated.