Wiring Problem Check Engine 2000 Toyota Avalon

I keep getting the same codes on my 2000 model Avalon P1346, P1135, and P1155. I have change all the O2 sensors(3) and both camshaft sensors, I am still getting the same codes. Toyota service found a wire not connected to anything and they think it may be part of, if not, the problem. It is a gray wire w/ darker gray or silver stripes around it on the passenger side of the car it is coming from the wiring harness going into the cabin. It has power on it, 12v and if I unplug the 15a fuse to the EFI#1 or the 7.5a fuse to the EFI#2 or pull the EFI relay the voltage goes to 1 to 3 volts and fluctuates. I have the Haynes book for this model car, but I can't find a reference to this wire. It is coming out of the wiring harness where the wire to the spark plugs at Cyl. #1  are coming out but there is no connector or other wire in that area that it seems to go to. I am open to suggestions at this point. Dealer estimates between $400 and $1000 to fix sensor problems.