hey guys...

i just picked up a 97 civic lx automatic for a commuter car. when i start the car, it seems to idle fine. It also drives fine. however, when i put it in gear (reverse or drive), the idle drops significantly and it feels like it is going to stall out. the other night it was cool out (50 degrees or so), and when i put it in gear it almost stalled. there is no check engine light. Also, if i am on a level surface, when i am in gear and take my foot off the brake, the idle goes up. If i hit the brake again, the idle gets rough. any ideas?

thanks in advance