noise when starting

Hello group,

I just purchased my first Tacoma last month. It's a 2012. I went to start it yesterday after work and it made a loud sound that was similar to a high idle noise. It lasted for about 5-10 seconds and suddenly stopped. It's definitely not the cold idle. This was almost as if something else was turned. Any ideas? I took it to the mechanic this afternoon, but fear it might not happen when they go to look at it.

Thanks from New Hampshire

 

Sounds like the air injection pump? I don't notice mine most times, but it can make a racket when you do hear it.

 

Agreed, sounds like the air injection smog pump. My 2012 does the same thing.

 

Normal, smog pump doing it's thing.

 

Thanks to all who replied. Mechanic says air injection pump is failing. Told me it's about $1300 to replace and said its under warranty by Toyota, but only when the check engine light comes on and has the code. Anyone have this replaced or should I just ignore it? Thanks