Alright so whenever i got my 91 civic wagon recently it started like a charm, but the second day i had it i let it sit for 3 hours and it barely turned over (i had to throttle it). SO i bought a new starter, needless to say, it worked good the first few times, but the same problem persisted. so i changed the fuel filter, and its been working great all day, until this afternoon ( i had let it sit for 7 hours) and it refused to start. So we threw gas in the intake and it just barely started. keep in mind after it starts it runs like a champ. What in the world is going on here!?! (the fuel pump is new aswell)

 

Im taking the crank is strong and you have checked for consistent and strong spark
I would look at your spark plugs and see if they are covered in fuel after the car sits for long period. I would suggest leaky fuel injectors. But i would like to see the spark plugs first

 

Alright i post tommorow norning, thanks