ok so my brother has a 1990 lumina with the 3.1L engine, and it was running bad, so me and my dad changed out the plugs, and at first it seemed good, but then it was odd, when cold the engine will idle up, then down, and continue for a while, when warm the idle is so low the engine almost wants to die, and it shakes in every direction, then if you put it in drive or reverse, it'll do it again, if you let off the brake so the car will start moving, it will kind of sputter along then it'll just increase engine speed all on its own and take off on you, we didnt road drive it yet so we can tell if it'll continue or not, but this is really crazy, any ideas from anyone would be awesome!

ok, so my dad removed the idle air control selenoid and heard a loud pop, like a backfire, put it back on, and we found a vacuum line that fell off the back of the engine, put it back on, and still ran bad, let it sit, started it back up, and it runs awesome, no problems at all now, so i guess this thread is closed