WHOA THERE FELLAS!!!! It aint quite as easy as tapping the feed wire. There are also two built in idle validation switches in the APPS / TPS. The TPS is a potentiometer, not a rheostat. But a rheostat can be used to manipulate the voltage to ECM, but
be absolutely sure to diode protect it!
I may get slapped for this, but you need to manipulate several wires at the TPS to make it work.
The LB/BK wire is the voltage to ECM, this is the wire that controls the engine speed.
Do not exceed 4. 5 volts!!
The BR/OR wire is idle validation switch one. This wire must be disconnected as voltage is applied to the LB/BK wire.
The LG/DB wire and BK/LB wire must be tied together to make idle validation switch two active. This must be done as voltage is applied to the LB/BK wire.
I would recommend using a do-it-yourself circuit board, some small relays and diodes to do the switching, and a rheostat or resistor to do the voltage changes. If you are electronically minded, it's not a hard process. Just takes a little thought and planning. Everything you need can be found at Radio Shack!
I've built one with a potentiometer so that I can dial-an-idle. It's cool. Nothing like the quality of the PS High Idler, but a lot cheaper, and I had to splice the wires, not just plug it in

. No biggie.
Good Luck,
Kris