I'm having problems with my 2003 Volvo XC90 2.5T engine dying at idle after starting it, unless I rev the engine to around 2K RPM for a minute or two. There is no check engine light/code coming up. It also seems as if the ere is a loss of some power. Could this be a turbo problem, perhaps with the turbo boost control valve? Any help steering me in the right direction is appreciated.