Do you have a reusable air filter?
 

Here's an idea....I had the exact same think happen on my Ford Explorer, It would just seem to fire then shut off immediately, I too check fuel pressure and it was fine (just like you).

The problem turned out to be a dirty MAF sensor, the oil from my recently installed cold air intake's filter was messing up the MAF sensor, I pulled it out, cleaned it with some brake fluid, put it back in and VOILA the truck fired and idled fine.

Worth a try, sounds like a MAF sensor issue to me.

Piper

This may not be fuel, maf, cps problem at all. I've seen many problems with immobilizer or key recognition. You may have a key transponder failing. If you have another key, try using it and see if the problem goes away. If it does, switch back and see if the problem reoccurs. I have a VW that had the same symptoms you've described, and when it wouldn't stay running, the immobilizer "key" symbol would flash. It would just start and die several times. I'm not sure if the Boxster has an immobilizer symbol as I haven't been able to check mine (in storage till spring).

Any solution
 

Hello,

I was just wondering if you ever found a solution? I have the identical issue as you described. The only thing I can add is that the 2 times this has happened to me, both days were hotter than average 31C [90F]. Fuel pump, MAF and CPS are all functioning correctly.

To my ears the instant "shut down" gives me the feeling it's not fuel, but spark related... In my experience fuel issues generally involve a bunch of coughing and sputtering before the engine dies... This is instant, car runs as expected for about 1.5 seconds and then shuts off like the ignition was turned off.

Immobilizer issue sounds plausible, but does anyone have any other opinions or experience?

I’m having this problem as well, did the original poster get if figured out?

When I had this problem it was related to a giant vacuum leak I created when replacing the starter. The car can only compensate the mixture so much. The fact that it starts seems to suggest fuel and spark are there, but air could be the issue. Just a thought.

My problem turned out to be a bad fuel pump.

Ignition switch perhaps?