2005 Buick Rendezvous Engine is loud

Does the engine idle normally? As far as the the high RPM's, that could be caused by a throttle position sensor or idle air control valve. Has the check engine light come on? Also, have you checked the entire exhaust system for leaks? Finally, does it sound like an exhaust leak or a ratteling?

OK, took the car for a spin and did a couple things after reading your reply. The car idles normally, and I couldn't visually see anything wrong with the exhaust system. Check engine light has not come on.

The sound it makes is similar to the sound it makes when you downshift at high speeds, except that the rpms are low (1000). I did find two things though - the sound is there when I shift into neutral, and the sound is still there, even when I turn the engine off. Sound seems to start / go away at a speed of about 20 mph. Do you think it might be CV joints? Wheel bearings? Something else? How I do figure out which?

Thanks,
Todd

Todd:
A wheel bearing could make that type of noise. Here is how to check. When you hear it, make turns. If the sound changes, chances are it's a bearing. Let me know what you find.

My wife took the car for a spin this morning, and found that the noise is better turning left, and worse turning right. Seems that the left (driver side) tire is the one making the noise. So it sounds like I need to change the left wheel bearing.

Very much appreciate your help!

-Todd

That sounds correct. Make sure the tire itself isn't the problem.