Lately, when I'm driving at higher speeds, like 65 mph and over, I can hear a high-pitched whistling. It also happens when I floor the gas. What could be making this noise?
This generation of Toyota Previas has a known issue with this that is typically related to something called a "flex pipe" which is a part of the exhaust system that sits in front of the catalytic converter. The fact that it fluctuates as you accelerate makes sense since the higher the engine RPM’s, the more exhaust flow runs through this flex pipe. To verify this as the issue, a professional from YourMechanic can inspect the sound in person in order to determine what should be done.
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