2000 es300 Buzzing coming from the engine

[Clo]

I have,a Buzzing noise when I initially start the car then stop after a few seconds. I had the oil pressure switch replace and the right selnoid.   It runs fine but I need to get rid of that sound.  

[gbhrps]

Clo,

I have this same issue (but I don't find it annoying) on one of my toys, a 1990 300ZX, and its the electric fuel pump pressurizing the fuel system when I turn the key to start the car.

I would wonder if this is the issue you have, its perfectly normal, but in your case its harmonics are louder. If it bothers you that much, take the car to a good independent mechanic you can trust (check with your friends for who to go to) and ask the mechanic to listen and give an opinion. It shouldn't cost you a thing, but the dealership will want to take the car to the service area, and I guarantee there will be a bill.

In future, update your signature to include the year, model, and mileage of your car. This info will quickly point out where we should be looking for a solution to any issues you may have. Good Luck!