[woodsman]

With a Durametric you can check for codes. Durametric is a private company not affiliated with Porsche . A dealer has an even more complicated tool for diagnostics. A check engine light illuminates for emission- related codes ONLY so you may in fact have a code(s) and not know it. Goggle Durametric and you will see the 'enthusiast's' package costs $287. You need a laptop and once you plug in the durametric you have access to the whole array of diagnostics on the car. You can test run some systems to see if they're functioning and any codes will lead you in the right direction. It gets complicated and may not interest you but it can save you a small fortune.
Testing fuel pressure requires a common fuel pressure tester and can be found for $30-50.
It could also be spark related, especially since the new fuel pump cured the starting problem but not the other. Also the fact that it happens after you hit a bump is significant- would seem to indicate something is loose...