My brother picked up a 97 s10 recently and has been trying to get it somewhat reliable to drive. We have replaced plugs & wires, checked for vacuum leaks and he is hesitant to throw too much money at guessing what part may be bad. It has the small 4 cyl (2.2 maybe?) automatic, 2wd. It runs great when it is dry outside but, as soon as it rains it stumbles all over itself and spits & sputters. Any suggestions on where to start? i'm thinking coil packs but want to see if there is a notorious issue any has dealt with or heard of.

 

sounds like you are in the right ballpark, something on the high voltage side. A little trick we used to do is take the bulb out of the underhood light and when it is bitch black outside start it up and look at all your wires and coil packs/not familiar with them at all/ If there is a voltage leak you will see the "blue" glow or see the ark, if need be pray the wires and stuff with water,not a hose but more like a sray bottle. Hope this helps.