I've searched and searched but can't find any references to this. I'm getting an audible warning type beeping sound on occasion. This appears to be happening when I'm traveling at slower speeds and using the engine for braking. For instance this morning I was descending a long hill in a lower gear and the sound appeared - it's a short series of audible beeps spaced about one second apart. First time I heard it, I was looking for a truck sounding a backing up signal around me. This morning, I pulled in the clutch and revved the engine slightly, and the sound stopped. I can't find any references in the owner's manual to this. Does anyone know what this might be?

Hi there, in some models there is a check valve in the fuel return line at the tank´s bottom, wich is known for making funny noises. When you are coasting or engine braking there is a surge of fuel thru the return line, this may cause the noise.
Just guessing
Best regards
JAP