It's been doing this for the 3 days. I go in the morning to start my car for school and it cranks for like 5 seconds before it will even start. What's goin on here?
Is it cold where you are? Most of the mustangs on this site hate to start when it's cold outside... I know mine likes to die when it is cold.
Have you changed your plugs/wires/etc. recently?
If that doesn't do it, you can pull the trouble codes out of the computer really easily! (you only need 2" piece of wire and the codes come up on the CEL)
Also, you can cycle the key a few times before cranking for the first time. If it catches immediately after doing this, it would seem that fuel flow is lacking (repeatedly priming the pump helps it out).