Rough idling on next start after car has been parked at an incline for a time

[her209]

My best possible guess is that its something with the fuel delivery system. Perhaps the "crap" at the bottom of the fuel tank accumulates near the inlet of the fuel pump and starts to choke the system?

 

[LTC8K6]

Fuel draining back out of the lines and letting air in?

What happens if you turn the key on and off a few times first? That is, prime the system a few times before trying to start. Pause in the on position a few seconds each time.