Hi, my name is***** sounds like you are describing a vacuum leak from inside the car. The noise could be coming from the driver's door lock or one of the other locks. You can disconnect the yellow vacuum line under the hood next to the brake booster that feeds the vacuum door locks to see if the noise goes away.
Let me know what you find.
If you only hear the noise when the engine is running I would have to suspect you are hearing a vacuum leak inside the car. You can try disconnecting the other vacuum lines that lead into the cabin and see if the noise goes away. If you hear the noise with the key on and the engine off I would suspect an electrical noise. If that is the case I would try cleaning all of the fuses. You might be hearing a faint sound from the door ajar buzzer.
Okay, if everything is okay with the vacuum lines disconnected I would suspect a leak in the vacuum system for the door locks.