shaking at high engine speed

[3rdChevynow]

Originally Posted by bigrod118

well unless the mounts and brakets themselves are bent or damaged, they shouldnt need repalceing, what you would have to replace is the bushings. I nkow they sell polyurathane ones for the top, but im not sure about the bottom, you might want to look around, polyurathane is much better than the stock rubber ones. but heres a link to the top ones.

I suppose they do call them motor mounts, but they really are only the bushings.

http://www.3800performance.com/Merch...roduct_Count=0

An update,

The engine shaking at high speed has completely disappeared after I had replaced the front upper bushings with the performance ones that fix well the enigine movement. Also, the strange transient electronic sound during acceralation has disappeard. It was well the engine mounts that cause the problems, combining apparently with other issues such as vacuum leaks.

The engine noise became somehow louder during acceleration, maybe because of an unbalanced vibration between the new upper bushings and the unchanged lower mounts whose clicking sounds can still be clearly heard time to time. That is another problem to fixe in the near future.

By the way I have replaced the Dexcool with the Prestone extended-life coolant. Next driveway-project will be the replacement of the intake plenum and the EGR pipe tail on the lower intake manifold.

Thank you again for your inputs, guys.

James