I have a 99 1500 5.9l. That I just picked up. It has a hissing sound between 1500 and 3000 RPMs once I step on it, it goes away. It idles fine and doesn't backfire (those are the things I've seen common on web searches). Any thoughts as to what it could be or what I need to do, if anything. This is my first ever dodge, so I'm not familiar with what is common place with these trucks.

 

my g/f truck does that too, it's a 2000 5.9, i have yet to look into it caue it's not really hurting anything i dont think and she has bigger problems then that sound... but it is def annoying!