New LML with 2200 miles has a bad rattle that can be heard out side at idle. It vary's up and down in volume. I put the truck on my lift and it sounds as though it is coming from under the bottom of the engine in the crank case. The noise can be heard best from LF fender well. This began after reciveving the P0299 underboost code twice yesterday. Any ideas? I plan on going to the dealer Monday but as we all know I will A either get my truck hacked up by a tech or get a sideways head look followed by there is nothing we can do.