1998 Chevy Camaro Cold Starting Problems

Recently my car has had problems starting from a cold start. If I let sit for about 10-15 minutes and try and start it, it starts fine. But when I let it sit for more than 30 minutes it struggles to start. My engine light is on but only because I dont have a catalytic converter, and I had a diagnostics done on my car to see if any sensors were out. The fuel pump checked fine and I replaced the fuel filter and spark plugs and everything else recently. The diagnostics said that my fuel pressure regulator was a little low but thats it. I cant figure out what it is. Im thinking its something little. Can you help.