intermittent vibration at 45+mph on 2000 Lumina

[scottjohnson]

I have a 2000 Lumina that has developed a intemittent vibration you can feel in the seats and steering wheeel at highway speeds. Symptoms:Comes and goes and lasts for 4-5 seconds then repeats after 30 seconds or soOnly does it when vehicle has been driven for 4-5 miles or when vehicle is warmsome vibrations are stronger than otherstires bave been rebalancedproper inflation in tiresdoes it in drive and overdriveput vehicle in neutral at highway speeds and it still does it.replaced plugs & wires thinking torque converter was shorting out thru plug wiresI am thinking wheel bearing but am not sure. anyone have any ideas or has experienced the same, please advise.I have had 2 service depts diagnose this wrong. 1 GM dealer and 1 independent service garage.Thank you

[Jprice90]

it kinda pulls back and forth? mine does the same, but when i give it gas it goes, let off it comes back, someone had said torque converter shutter, or something like that