2003 Boxster - Crank No Start

[apac]

So I am having my first problem with my 03 boxster.

Pulled it out of the garage last week, as I was waiting for the garage door to close the car started stuttering and then engine shut off.

Tried to restart, it cranks but engine won't run.

Here is what I have done so far.

1) Check for codes - No Codes present
2) Replaced battery with a new one
3) Replaced DME, Ignition/O2, Blower Engine Comp and Fuel Pump Relays with new ones
4) New Ignition switch

Car still wont start! I left it cranking for >15 seconds and was able to get engine run for a few seconds, but it felt as if only 1 or 2 cylinders were running, then it shut off and won't start. Still no codes present.

Has anyone had a similar issue? If so how did you get it fixed? What else should I check? Thanks!