Recently purchased 2007 SE with 91,000. When motor first cranks, RPM immediately hits 2800-3000...doesn't matter the outside temp; cold, cool, warm, or hot. It quickly steps down to 1500, which is an expected high idle speed and then drops to normal 750-800 RPM. Does not do this if motor is warm from earlier driving. Never owned a Nissan; anyone else seen this?

Thanks