3Rz connector help

Hello, i had a 2.7 3rz supercharged that blew up last summer and spend the winter preparing my new engine, now that it's done I dropped it in the car and connecting everything. By the time i was done I lifted the car to do some adjusting and stuff and realized there was stiff a connector left, i spend hours trying to figure out where it went and my engine cranks but wont start, I have spark and gaz
This is the connector, any idea where it goes? and if this may be the reason why it doesn't start?

 

What year is the truck?

 

2000

 

Get a pic with other things included. What corner of the engine compartment?

 

that's the thing, it was dangling under the car, it's in the same part of the harness as the cam, crank and throttle sensors

 

What side of the engine compartment?

 

Looks a lot like an o2 sensor plug?

 

I thought so at first but since it's cat delete and the other o2 sensor is already plugged in to another connector

 

could it be the cat wiring just left for dead ?
( the guy i bought it from did all the mods so i have no clue)

 

Where does the harness connect to the main harness at?

 

i dont know, probably on the other side of the firewall or it's all under the protection casing of the harness as this is a swap and the harness is custom

 

The connector resembles the cruise control plug on my truck, although I don't have CC.

Not sure but, with the oil residue on the connector, it could attach to a low oil sensor near the oil filter.

 

I don't have CC either so it may be a left over plug but i'll check near the oil filter and let you guys know

 

You have both o2s accounted for? Im still leaning towards o2 plug

 

Just to be sure where are they?

 

One on either side of the cat

 

I have no cat so that solves the problem

 

What are the 4 colors of wires? Looks like two are red/black, white/black?

 

Red/black
White/black
Orange
White

 

What you have there is the Air Fuel Ratio Sensor Plug (Bank 1 Sensor 1). Like others have posted, that actual plug is meant for an O2 sensor. Should be for your pre-cat sensor.