Low RPM vibrations

[hvyjnkr]

I did a search, but to no avail. after the high idle turns off, the skid plates will vibrate terribly at idle to around 1300 rpm. I tried tightening them up, but they didnt feel loose. Has anyone ever experienced this symptom before and how did you cure it? BTW I have an 04 2wd Tahoe LT. any sound advice will be greatly appreciated.

hvyjnkr

 

[jasnem]

could be the heat shield on the muffler

Mine would rattle like crazy at idle. Welding it does no good, it just works it way loose again.
What I finally did was got 2 of the biggest hose clamps and connected them. Wrapped them around the heat shield and the muffler then tightened it. Havent rattled since.