What? Not MAF Sensor!!? Grrrrrr!

[14Boxter]

Symptoms: More cranks to get engine to start, rough idle, Check eng. light. Added injector cleaner to fuel. Problem resolved. Added more fuel, no injector cleaner, after 7 mi. engine started to bog down when accelerator was depressed too rapidly. Next day, engine will only run for a few seconds and then die. I can smell gas, and engine needs to sit before it will start, and then again, only run a few seconds before it dies. Replaced MAF sensor but to no avail. Also cleaned throttle body. Unfortunately, I disconnected the battery to clear the memory so that I would get a current fault code but this was before I discovered the engine wouldn't run. Would bad upstream O2 sensors cause the engine not to run? I'm going to check for vacuum leaks next.

Any insight would be appreciated. Thanks in advance!

P.S. 2001 Boxster S