1993 Camry LE that runs great!

about once a week when starting up the car, I have to hold the gas pedal down to the floor and run the starter for about 5 seconds before the engine fires up. when the engine kicks in, it misses for a few seconds and then runs fine. I have to keep my foot on the gas to ensure a higher idle so it doesn't stall (another symptom of this cold start problem)...

any thoughts on what could be wrong? Most of the time it starts up fine, but about once a week or so I go through this ritual to get it started and up and running...