If you're using the fuel injection system, you'll need sensors such as the vehicle speed sensor and O2 sensor, etc. Otherwise you'll get a constant "check engine" light, and if you're using a transmission with a lockup torque converter, it won't function without all the sensors in operation. You'll also need the in-tank fuel pump and the wiring to run it.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!