some advice

i've read through these forums,,so i'm not just postin the stalling topic because i haven't tried to find out first...its a 96 bonneville 3.8,,,when i put it in park and turn off the a/c the idle will jump around then die,,,also when slowing or coming to a stop,,or if the cruise controol is on and i tap the brake it will stall on highway,,,i have replaced the egr valve and the idle air coontrol valve as recommended from other posts here,,,but i still stall and haven't read these exact symptoms from other posters....any help or other ideas would be appreciated,,oh and there is no engine light on and i dont have any trouble with acceleration,,i dont know if a diag would pick the prob up or not,,its hard to spend money and get screwed....thanks