[Al Skierkiewicz]

Beth,
There are a number of conditions that cause the engine to lose oil only when running. I would start the engine and let it run for ten minutes or so and then pull the car back to check underneath. If there is no puddle then it must be going out the tail pipe (see previous posts) You may need to take it to a techie who can give you a good idea as to where it is going.

As unlikely as this sounds, I have come across more than one instance where someone has swapped the dipstick with another car. That makes the dipstick too short and filling it to the line on the dipstick puts in just enough to barely turn off the light. Get it checked out, Murphy says it will fail you when you need it the most.