this started a few days ago, i was otw to work and was coming to a red light and the car was rumbling, then died, it starts again after like 10 seconds, and does it again at the next light. i get to work and it sits for a few hours and i get home fine, now as im driving to work today it rumbles to a stop, then overheats and steams from the coolant cap, i pull into a parking lot, let it cool down, then it idles fine at like 180 fahrenheit if not lower, i turn it off let it sit, now it doesn't... Broken down right now, need some pointers