Chevrolet Repair: 2004 Tahoe - annoying vibration, drivetrain, vibration

Question
I have a 2004 Tahoe which is in tip top shape, however there is a serious vibration in seemingly in the drivetrain when iddling in traffic with the brake pushed.  Chevy says "the computers say everything is fine".  Is this a common problem?  Chevy says it is ... although there was no vibration on the test drive.  Help!

Answer
Hi Pete, Check both engine mounts to make sure that they have clearence between the engine mount and frame mount. If it is too tight loosen all bolts and jack the engine up, then adjust the frame mount all the way out to make more room. The only other thing I see is a reprogram for a rough idle, this will go away if you rasie the idle just a little. So if it doesn't go away this one isn't you.

Hope this helps

Mark