ASKED BY: noumenon 0 0 0 3 0 6 32 ASK DATE: Feb. 1, 2010 CATEGORY: Mechanical | Engine Surge Share:       Vehicle: 2004 GMC Envoy 2WD Engine: L6 3.4 L Transmission: Automatic Drivetrain: RWD Current Mileage: 93000 What would cause the engine to surge up and down while in park COMMENT BY: way2old 0 3 9 9 2 0 80 COMMENT DATE: Feb. 2, 6:13 PM QUALIFICATIONS: ASE Certified Site Rank: 2 Have you tried cleaning the throttle body? Try that first then look at the Idle Control valve. Username: Password: Remember Me  Sign Up  Forgot Login? Year of 2009 way2old 3 Posts. 0 Answers. Mech Rep: 80 Mileage: 39920 swatkins 1 Posts. 0 Answers. Mech Rep: 74 Site Mileage: 5285 About Us | Contact Us | FAQ | Privacy Policy | Site Map Vehicle Aid © 2005-2008. All Rights Reserved.