for all of you TBI gurus
 

im looking at buying a 89 s10 with the 4.3 v6 with tbi on it. the truck runs fine when youre driving and also at idle in park or neutral, when it is in gear and stopped though the truck shudders. what could be causing this?

describe shudder

kinda like when a car runs rough and its gonna stall out, that kind of shudder.

maybe the IAC is loaded with **** or theres a vacuum leak, id start there

automatic trans? if it is an auto i would guess that the TC lock up solenoid is letting go.
just reach under the truck and unplug the 4pin weather pack connector in the trans(white connector on the drivers side) to test it. it is perfectly safe to leave it unlocked, it may cost you a few MPG at mid speed cruising, shoudln't notice too much of a difference on the highway or stop light to stop light.

cool, like i said im trying to determine to build up the v6 or do a v8 swap. the v6 would be a cool buildup not many people do it