RPM thing: What was the weather like? Your choke could be ill if thats at all possible..... did it fix it self after a few mins? How did it drive? Did it just start today?
The oil leak thing i have no idea about. Im not even sure this is related but check the oil filler cap for a white substance. Also whilst the engine is idling check to see if there is any bubbling...
White substance - Headgasket failure - could be big bucks to fix, but you should get it done asap and not drive the car too much.
Sory i cant be more help!
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