2004 T3 Toyota Tundra Tach Wire

I assume you have the 4.7 V8 - I have 03 Tundra TRD with 4.7...according to a wireguide sheet a friend sent me, each cylinder has its own ignition coil with a 4-wire harness. Three of the four wires are found at each coil - the one wire that is unique at any of the coils is where you can get a tach signal. Also, behind the glovebox is an ecm in the upper right hand corner..pin 16 of the 28 pin connector is also suppose to be a tach signal. I used this in my application but havent got it to work yet...still trying to figure out if its signal or something else....