what is my computer and how do I tap into it with a regular computer. I'd like to do some fine tuning on my car. 89 iroc 5.7l auto.

do you mean what is your computer or where is it.the computer runs tbi or multi port injectin system and all your sensorsand ignition and distributer and all that good stuff.the computer is on the passenger side behind the dash you should have an iroc emblem on the dash its directly behind it.you will probably have to take it to a garage to have anything done to the computer but there is a plug in on the bottom part of the dash on the drivers side

Accell used to offer a lingenfelter designed software setup I think it was the CALMAP thingy, You could plug a laptop into a GM harness and adjust all kinds of things. Spark curve, fuel map timing, etc...
do an inrternet seach for calmap software, I remember the kit was kinda expensive, and in the wrong hands could do a ton of damage to the motor.