So my Dad's 06 screw 5.4 V8 has been having a weird noise intermittently. It sounds like a rattle or marbles in a can but never happens at the same RPM. It seems to be coming from the exhaust but I can't find anything lose under the truck. We can't get it to make the noise with it sitting still so I can't exactly pin point the location.

Looking for ideas on what it may be and would appreciate any ideas to try.

Thanks

 

I forgot to mention that the noise only occurs while accelerating when it does make the noise.

 

I think I have the same noise did you find a solution because it is killing me not being able to silence the rattle.

 

Could be a cat or pinging from your motor.... Does he have a cold air intake?