[65comet]

Fuel filter is a good start if it hasn't been replaced in awhile, but my guess based on what you say is a pretty hefty vacuum leak. All the extra air getting into the intake system is leaning out your fuel most times for that type of starting issue, and the shot of starting fluid is what it needs to get past it now if the leak is getting bigger. There's tons of videos and forum entries on how to check it, you just have to search a little. I's usually go into great detail, but I have to leave and take care of a minor family emergency.