A common problem is the exhaust headers. The ac drip line drips on the headers and needs to be relocated. My friends 04 did the same thing.
Take a hose and stick it in your ear and try to locate the problem. Use it like a doctor uses a stethoscope. Of course, the sound will get loud when you locate the problem.
new engine,1.7 rocker arms,Pipes exhaust, shorty cats , shorty headers,under drive and overdrive pulleys,4.2 upper plenum, throttle body spacer, cold air intake, stage one clutch, shorty shifter, and tune. 8.8 in storage