Loud Rattling/Pinging Sound outside of truck at Idle

[Metalhead]

Ever since I got my truck back from having the Hi-Pressure oil pump fixed, the truck sometimes has a loud rattlling/pinging sound at idle. The motor is running smoothly, no fluctuation in RPM or difference in performance. This sound reminds me of the way the old chevy suburbans would get that clanging sound to the exhaust at idle or low speed, like to metal parts rattling against each other. The truck has the stock exhaust on it, does anyone have any ideas?

Thanks

 

[BIG JOE]

From the Hip ? Don't know what all they took off to R&R the HPOP but.. when it's making the noise, move the Charge Tubes around a bit, see if one of them is touching something.. Also, there is a pinch weld on the pass side firewall thats purdy close to the down pipe..

Joe