Ive got a strange sqealing coming from under the pass side of the dash of an 06, but only under heavy load/high boost. It almost sounds like when you take a piece of paper, pull it tight and blow hard on it. What under the dash would be under boost??

Kyle

 

maybe check your intercooler. i had the same problem and come to find out my 05 plastic intercooler had blown a gasket. it also shut down on some of my power also then a code 0299 came on then my engine light decided to come on after that.