Hey, I recently pulled an '88 5.7L to put into a 1990 4runner. I figured I would figure out the throttle body when I got to it. Well now i've gotten to that part and everyone always says how simple of a system the throttle body is but i'm begining to disagree. I originally was going to use (parts) of the gm harness, but now i'm not sure what all I need to keep. After reading up on the subject I found out there was more to the engine than I originally thought. For instance the knock censor, and 02 censors. Will I need the gm computer? I recently found a wiring harness in summit but it's 360 dollars which is hard to shell out on a students budget. I guess what i'm trying to ask is what is the bare minimum needed to run a throttle body injection?  

The simplest and cheapest way is to integrate GM wiring harness and ECM into truck. You will need ECT, O2, MAP, TPS, IAT and VSS. It is pretty reliable when setup and can rival a carb in dependability. You are also going to need a 14 PSI fuel pump and a return line.