I get this popping sound under my truck directly under the passengers side floorboard when my truck get hot. I went on a trip and after driving over 100 miles or so I heard a pop that sounded almost like metal flexing under the passengers floorboard. My wife sad that she could feel a vibration in the floorboard also. I pulled over and took my flashlight and looked in the wheelwell and everything looked fine. The truck doesn't do this on my everyday commute. It only seems to happen when I drive it for a while. I would appreciate if anyone could explain what this noise might be. Thank You!

 

do you have a after market exhaust system?do you have a load in the bed of the truck when this happens?

 

Mine did the same thing when my water pump was going out. Why would exhaust or a heavy load have anything to do with this?? Mine is lifted with 33" tires.

 

i had a 1999 z71 with dual exhaust and when i had my 4 wheeler in the bed i would have a very bad vibration on the right side,lived with it for a while till muffler guy fixed it before i sold it.