Ok, I replaced my idle air control valve and it idles fine at 500 rpms, no small shaking or anything. But recently I discovered that the car will out of no where want to stall at a stop. I did a self diagnostic check and the only code that came up was P1684. That was due to the fact I cleaned the battery terminals out real good.I just bought some spark plugs and boots cause I think my car is due for replacement. I was thinking, for it to stall at a stop out of no where it would have to be a sensor right? I cleaned the throttle body out real good and it helped out some but not enough to make the stalling go away. If I come to a stop, it might idle fine for about 25 seconds and then want to stall. Also I put it in park and it stalled, not all the time but a few times it has. any thoughts???