Z24 Starting Problem

I have a 1989 Chevy Z24, and up until now everything has ran like a top. When I attempt to start the engine, it starts to crank and then is followed by what sounds like a very odd rev in neutral or even an odd sounding engine firing...its tough to explain... but the car doesn't start. After two or three times, it will start. It just started doing this within the last week or so, and every few days it seems to take a few more tries to get it fired.....

Please any ideas?

Thanks in advance...