The muffler heat shield may become loose on the muffler causing a rattle or popping noise. Our technicians tell us there is a kit available from GM to correct this problem.Google+
Car Problem Reports
GMC Yukon XL 1500 Popping Noise From Muffler Heat Shield
GMC Yukon XL 1500 Problem
Average Mileage: 81,000 mi (43,000 mi - 119,000 mi)
Visitor, 2005 GMC Yukon XL 1500, 119,000 mi
major vibration/rattling noise from muffler heat shield at 1100-1200 rpm only. Makes noise in gear or out of gear when engine/exhaust are hot only.
Visitor, 2005 GMC Yukon XL 1500, 43,000 mi
Popping and pinging noise from exhaust system. Not yet addressed.