So just today after driving to work, I noticed that there was a fluttering sound coming from the engine. More or less, it sounds like a piece of paper hitting a running fan. When I put it in park, I gave it a couple small revs and the fluttering sound occurs when the rpms are coming back down to idle after the rev. I haven't checked much yet, but I was wondering if anyone else has experienced this kind of an issue or what it could possibly be.
If you have any further questions about the car that would give extra information, feel free to ask.
The car has around 113k miles if that helps at all.

 

I had that happen recently and it seemed to go away after topping off the oil. Lifter tick, maybe?

 

I have a '95 SC400 and it has the same sound. I dont think it is related to engine as there is lag in rpm drop between the engine rpm and the sound.

My sound memory bank matches the sound to old propeller (from airplanes) referred to as feathering ...

So that tends me to believe that it is the hydraulic driven air fan. Although my stereophonic hearing tells me it seems to be entering the cabin near the passenger wiper arm pivot. But it can be deceiving.

For now I have raised the volume or radio to drown it.

Salim