Recently my 3.1 Regal has been having trouble accelerating. I don't seem to be getting enough power in the low gears. When I do accelerate, it's accompanied by a humming noise that is similar to a high engine rev, but the tach is showing normal levels. I thought it might be a clogged fuel injector, although I didn't know what to make of the noise. Fuel injector cleaner didn't seem to help much. I'm suspecting it's a throttle sensor. Any suggestions?

I would check your air filter. Your engine may be just starving for air. One other thing I'd check is your alternator. They have a tendency to hum or whine when they go bad. The voltage drop can sometimes cause sluggish performance.