Engine Whine @ 3,000RPM
 

I have an '07 S. When I hit about 2,500-3,000 RPM the engine power drops markedly and goes from a nice standard hum to a louder, more high-pitched sound. It sounds like a combination of a manifold leak and a transmission slip. But here's the funny part. It's been getting worse over a nine month period and seems to improve as the car warms up. I'm at a loss. Any chance this could be as simple as an electronic settings reset? Do I just disconnect the battery for 10 minutes and hope for the best here? Thanks for any advice.