99 Sentra start/no start dilemma

[buckhardy151]

Daughter moved car, then tried to start and boom, won't start. checked for fire-good. checked fuel pump fuse, pump, pressure-all good. changed the fuel filter and car fired right up! While everyone was cheering, the guy behind the wheel turned ignition off after bout 45 seconds of idle. tried to start it up again. No go. Next morning-started, idled very rough, and only ran long enough to move it bout 20 feet. boom! no start again!!

Update: Day three and still no start. Yesterday I held accelerator down while cranking to see if any change. It seemed to lope a couple of times as if trying to start, but nothing. Thought there may have been a slight smell of gas, but may have been residue from reinspecting fuel pump in tank. No apparent leaks anywhere.

Can this be caused by the crankshaft sensor?

[MaximA32]

Are you getting any codes?

[buckhardy151]

No codes when machine hooked up, just a snapshot and that code was I think 0P400 or similar-EGR code and oxygen sensor. However I've been reading that the ECM nees to be switched to diagnostic mode? We didn't do that.