My 2000 monte is actin weird lately....if left idling for about 5 min when warm and i go to leave it will stall, it will restart but hard like its flooded...i've changed plugs, wires, fuel filter , cleaned the throttle plate, iac is fine, it will do this randomly , i notice it more in hot weather...i've noticed that it does run slightly hotter than it used to...I'm leaning towards clogged cat i notice that if i have my fott in one spot on the gas when its cold , or warm it will feel like it pulls away good then doesnt then does.... I'm stumped on this. any ideas what would cause this erratic idle when put into gear with stallin...and hitting the gas right away does nothing.