GM Service Manual Online
For 1990-2009 cars only

This condition may be caused by one or more of the following problems:

    • Broken balancer or pulley hub. (Replace all parts.)
    • Loose torque converter bolts. (Retighten to specifications.)
    • Accessory belts too tight or nicked. (Replace and/or set tension to specifications as necessary.)
    • Exhaust system grounded. (Reposition as necessary.)
    • Flywheel cracked. (Replace flywheel.)
    • Excessive main bearing clearance. (Replace as necessary.)
    • Excessive rod bearing clearance. (Replace as necessary.)
    • Low quality fuel.