Buzzing noise on deceleration only if A/C is off.
My first post. 2001 Mazda 2.5 V6 automatic with 112K miles. When parked, I notice the engine makes a buzzing noise on deceleration only if the A/C is off. So, if I rev it up and then let it go down, it buzzes for a few seconds. If the A/C is turned on and is cycling, the noise doesn't happen. If the A/C cycles off, the noise comes back on deceleration only. The buzzing noise does not sound like it's coming from the compressor, rather near the top front of the engine in the general area of the timing belt cover. Not a lot of action on the MPV forum, so I'm posting it here also since the 626 V6 is the same engine.