Irritation Vibration at Idle

[Hammer32]

My 2002 Tahoe has an irritating vibration that occurs at idle. Not serious, but just bad enough to bother the heck out of me. I took it to the dealer and no surprise, they said it was normal.

 

Since then, I have noticed that the end of the tailpipe is the part of the vehicle that really gets to vibrating while at idle. The tip of the exhaust pipe has a vibration amplitude of about ¼" or so.

 

Knowing a little about vibration theory, I knew the possible remedies:

1. change the input frequency

2. Change the spring rate of the system

3. Change the mass of the system

 

The easiest of course was to add some mass to the tailpipe. Through some testing I found that about 2lbs does the trick - completely eliminates the resonance condition. I cut a piece of 3" dia sch 40 pipe and slid it over the end of the exhaust pipe and locked it down with some short screws tapped into the pipe.

 

I've read that their is a TSB for this problem.  Something about adding a flexible section of pipe to help isolate the tailpipe from the engine vibration.  Can anyone help with this?

 

Thanks in advance.