I am having a problem trying to diagnose a rattle in or around the engine. It only occurs once the Jeep is hot. When taking off you can hear a rattle that sounds like maybe a heat shield. It gets really loud upon take off at 2K RPMs. Once the automatic transmission shifts and the RPMs drop then the rattle goes away. I cannot hear it once I get back up to 2K RPMs. It does not occur while in park or neutral but it does on all other gears, including reverse.
I haven't been wheelin' lately so there's little chance of rock or other debris damage.
I have crawled under the Jeep several time checking everything possible for anything loose, bent or broken but I cannot see anything.

Any ideas would be greatly appreciated.

2007 Sahara, Automatic, 4dr, OME lift, 33"s.