Unknown bolt function

I'm new to the forum since this is my first Tacoma so I apologize for what I'm about to admit.

I changed my plugs today for the first time after learning they we not 100k plugs.

I got a little zealous with the first one and remove both bolts by the coil. I realized the mistake when I removed the coil and put the mystery bolt back in.

Does anyone know what that bolt is for and if I have any thing to worry about by removing it?

I have an 09 4x4 sliver access cab sport 6 cyl.

Thank You
Bob

 

What side of the engine and front, back, or middle plug?

 

Middle plug passenger side

 

The one on the left side of the coil pack, not holding the coil pack down, is one of the valve cover bolts. Torque value of the valve cover bolts is pretty low, I'd just make sure the bolt is gently snug and keep an eye on it. If you see a slight oil seep then give it a touch more tightening.

 

Thank you! I started the engine after I finished changing the plugs ready to shut it down if I heard anything unusual. My fear was something on the underside would fall into another part of the engine. That's a repair I didn't want to think about.

Thank you again for your assistance!

Bob