Nah...it's got to be the fuel. I filled it up to about 3/4 full yesterday, and today it took about 10 seconds of cranking to get it going. Yesterday I also looked at the see-through filter that I put on the fuel line, and it appeared as if no fuel had come through after the first attempt to start.

There is no sign of a leak under the car, so somehow the fuel must flow back into the gas tank. HOW?!?!