Long shot question
 

Whenever I crank up my truck (2003 v6 taco) and get underway, there is a noise, almost like a whir that last for about a second, and it goes from a high pitch to a lower pitch. Really hard to describe this sound with words. It is not a problem it is obviously something happening by design. Just curious and I realize this is pretty undescriptive. But it happens just after getting underway after cranking up. Its not a problem noise its a sound of something happening. Anyone?

Something moving is warming up. :hillbill:

:wabbit2:

Cooling Fan Clutch?

that'd be my first guess too. fan clutch engaged at start up sounds like a loud whirring until it disengages. should be plenty noticeable if you open the hood first. does your truck have an electric fan?

That's exactly what it is. Situation normal.

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I dont think its the cooling fan clutch. It hard to describe, the sound is more of an "electronic" sound "schoooooooom" like. LOL anyway thanks

sound clip!

interesting. electric fuel pumps make a temporary sound at start up when they first pressurize. could it be that?

have you been able to locate it's source? is it definitely in the engine bay, or under the truck, or inside? maybe your phone can record sound with video and you can post it to utoob or something.

toyota mysteries are "fun". not!

It does sound like it is under the truck and not in the engine bay. I tried to get a sound clip with my phone and you just cannot hear it. It may be that fuel pump noise? Im not worried about it, I just always wondered what it was. Thanks for the insight.