so lately my truck has been making this weird rattle sound when I first start it up in the mornings, or even after sitting for a few hours...the rattle only last maybe a second if not less...sounds like its coming from up top of the motor maybe ??..truck only has 62k miles its actually upsetting me..truck sometimes sits for months at a time in my garage..other then that the truck will run just fine and smooth...just trew a code the other day saying " insufficient exhaust flow recirculation" something like that...

any input would be great guys, thanks...