2016 2500hd 4x4 WT
6.0 flex fuel

Pinging noise sounds like someone tapping on the exaust pipe under the front of cab. it doesn't do this every time, sometimes im hearing the same sound driving with the window down , and sometimes I don't hear it at all , any ideas ? It is starting to really bug me. sound or no sound truck is running fine

 

It sounds like what you’re hearing is spark knock - it happens when there’s more than one point of ignition in the combustion chamber.

This can typically be confirmed by hard acceleration once the engine is up to temperature. If it repeatedly occurs during hard acceleration (either from a stop or when passing), spark knock is the most likely cause.

The knock sensors are supposed to signal the PCM when this happens, but there’s multiple reasons why the PCM may not be responding.

Start by checking for diagnostic codes, even if the CEL isn’t on.