01 Montero Tach Wire

I'm installing a remote starter in my 01' Montero Limited. The system shuts itself off and requires that the tach wire be connected to the remote start unit. The info provided for my vehicle says it's a yellow wire on the driver side of the engine compartment behind relay box. All other wire information provided was very accurate but I cannot find this wire anywhere. I have searched for two days. Any help would be appreciated.

Actually, it is in the diagnostic plug. The inspection connector is on the driver side of the engine compartment behind the relay box. Usually though, I use the fuel injector wire on most cars.

Actually, it is in the diagnostic plug. The inspection connector is on the driver side of the engine compartment behind the relay box. Usually though, I use the fuel injector wire on most cars.
I cannot find the diagnostic plug. Is it an open plug used to plug a vehicle diagnostic computer into? If so, I cannot find anything that looks like this. Could it be anywhere else? Plugged into something? I was going to use the fuel injector wire but I have to remove the plenum to get to the injectors and it seems like much more trouble if I can find this tach wire. I appreciate any help you can give me.