change in idle sound between cold and hot

[JoaRodriquez]

I have 03 3500 mornig starts truck sounds good, run it for a while, and at idle the motor sound changes, like its missing. The truck has 229k on it recentley changed all injectors and fca, that made truck run better but that different tone at idle has me bothered. Any ideas

 

[rbattelle]

It's always hard to diagnose a sound over the internet. Why did you replace all the injectors and the FCA?

What lift pump are you running?

Ryan