Experiencing a thump as the ignition switch is released from the start position or as the engine starts

Bulletin number

00059

Component

Engine and engine cooling: engine

Summary

Experiencing a thump as the ignition switch is released from the start position or as the engine starts. This noise sounds similar to a rubber mallet striking the frame and occurs only on a cold start (the vehicle has been sitting for some time, usually overnight). The vaccum-actuated rear engine mount does not work properly because of insufficient intake manifold vacuum at start-up. Tt

Owners of these vehicles have filed 400 complaints in the engine category.