This morning was the coldest of the winter so far after a moderate ice storm over the weekend. Driving my 2001 S4 to work I noticed occasional power loss. Keeping a constant pressure on the gas I would feel occasional slight deceleration. Idle was steady. Maximum power acceleration may have been slightly low but I'm not sure. After parking there was a very faint smell as when oil spilled during an oil change bakes off.
Any guesses what's wrong?