Yesterday, while working on the 95 Jimmy swap; the motor tune was way out of wack. I managed to get the throttle stop torx screw out of adjustment not knowing what I was doing and now know why it has a cap. I could not get the idle and the throttle response to jive. I either had good idle and no throttle or throttle and poor idle. I tested the fuel pressure and it was good. After testing all the sensors with a multi-meterI and finding all the sensors in range I accidentally moved the throttle open a little and noticed the idle settle down. After adjusting the throttle stop torx the problem is solved. Yes, I know I shot myself in my foot to begin with by messing with this screw but I learned some valuable information. I've come to the conclusion what was causing the original problem was the MAP sensor. I don't think it was plugged in properly.
Sometimes we must go backwards to move forward.

 

MAP sensor improperly connected ? But the three wire plug should fit one way only as the slot is keyed ...
however , yesterday I had fun swapping out seemingly good MAP sensors on my '95 with (junk yard pulls for testing) and they all made the 4.3 engine run a little differently - none set off the check engine light . One was quite an improvement in drive-abilty and throttle response