My son has a 2008 300 with a 3.5l engine with over a 150K on it. He says it's not running right and in limp mode. We stuck my scan tool on it and do not see any codes. He said it could be one of three things: the switch or sensor on the accelerator pedal, the throttle body sensor, or what he is calling a Flashmaster engine computer located under the hood near the passenger side hood hinge (mounted to a cross member holding the dust shield for wipers). Can anyone give me direction? Thanks.