While in stop and go traffic today my temp guage went almost to red for about 5 seconds then back down to normal. After that i noticed it was idling weird while i was stopped. when i would rev it a little or start going some smoke would come out of the exaust momentarily. I pulled off the freeway and popped the hood, no smoke coming from under the hood and everything appeared to be normal. When i would rev it some smoke would come from the exaust and from underneath the car near the driver door, but none from the engine itself. Any ideas of what my problem is? would an exaust leak cause this rough idle and bit of smoke? Also when i got the car home it still had the rough idle but no smoke.... any feedback much appreciated.