Lately, whenever I shut my truck off I get this pinging noise that last for about a minute or two. Sounds like its under the hood, or even maybe from the exhuast too. Any Ideas what it is? Never had the noise before until recently.

 

i have that sound too, sounds like its the cat's!

 

It is your exhaust, cats, heat shield making the noise. I'm surprised you have never heard it as all of my cars have done this. Oh well, now ya know!

Wecome to DF.