95 EX Auto 166K

During acceleration (not super light feather) loud buzzing noise coming from passanger side of engine compartment, and seems to be more pronounced after the tranny shifts into 2nd. Took it in for a leaking radiator (replaced, $350 later) asked them to find out what was causing the noise. The garage was unable to find a cause, but did hear it. Thought at first it was a tranny issue, some sort of line buzz but no evidence of it was found. They also checked for some loose parts under the car and under the engine compartment, again no dice. It doesn't appear to be causing any issues but is driving me nucking futs. Any thoughts on this? It does not sound like pinging/detonation at all, and since its on the passenger side it doesn't appear to be the ac pully/compressor or belt. I am at a loss and don't want to take it to the stealership yet.

Thanks