when i'm driving, and i step on the brake to slow down, the rpms drop to just above 500, and when i do this and take a slow turn, they do the same, it doesn't do it every time, but most of the time. and even a couple of times while taking a turn, it seems as tho its goin to stall but it doesn't. also, when the car is idling, the rpms go up and down like 100rpms, but like every 5 minutes, they droip, the car shudders, and then they come back up. anyone no if this is some kind of sensor? maybe...