My car suddenly started not idling. That is, when stopping at red lights the engine kept reving on its own. The RPMs kept jumping from 2 to 3 without my putting any pressure on the gas pedal. I could hear the engine reving. The temperature gauge was also reading hot. This was within a matter of 3-4 mins. Any ideas of what the problem could be, as I'm clueless about mechanics. Any help would be greatly appreciated.