sounds like potentially a leaky injector(s). When you shut the car off the fuel line and rail remain pressurized until next start, but if you have a leaky injector, the injector will drip fuel into cylinder essentially flooding it causing the harder start scenario you're describing. If you wait long enough (ie. cold start) the fuel that would have dripped into the cylinder would have evaporated and this starting like normal. To troubleshoot, you can remove the fuel rail from the engine with the injectors attached and still connected to the fuel line. Turn the ignition switch on but do not start the car and place paper towel under the fuel injectors. This will pressurize the fuel line and rail. If you have a leaky injector, you'll be able to see which one is leaking. Could always be something else but this is what i suspect.