I get a high pitched whine while I'm on the phone:

• z130bt,  LG ENV2 phone.  BT connects right up within 15-30 sec whenever I get in the car.
• It's pretty low level volume but it is still clearly audible, enough to be annoying.
• It changes pitch when someone is talking vs not talking.
• It is the same whether the car's engine is running or not.
• I've tried touching the mic cable to see if my body grounds anything ... no effect.

Any ideas?

Thanks.  John