When I start my H2 I hear a loud rattle from underneath the vehicle. After a few minutes of driving the sound stops. I’ve heard two possibilities. The first told me it was my catalytic converter. The second is the that the muffler has become unwelded from a protective plate underneath and that I should just have the plate removed as it isn’t really needed. Has anyone had this happen to them as well or have any suggestions on what it could be? By the way, I’ve had no engine lights come on over this.

 

Sounds like a heat shield rattling, should be an easy fix, get under the rig, tap on the exhaust with your fist or rubber mallet in different spots, once you recreate the rattle, then you can figure out what needs to be done, sometimes as simple as bending the heat shield to gain some extra clearance.