Plug unplugged that needs to be plugged

[350chevy719]

Could someone tell me what plug this is for. It's been unplugged since I got the truck, doesn't seem to effect the truck....hopefully

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[350chevy719]

Sorry forgot to add this is 350 tbi. Excuse the dirtyness

 

[RyanMerrick]

Why don't you plug it in?...

 

[350chevy719]

I did just wondering what it was and why it would have been unplugged in the first place haha