Did you replace the distributor cap while you did the rotor? Its time to start troubleshooting...make sure that the wires are all in good condition, that there is no arcing ANYwhere (coil too). How long will it run until it dies? Few seconds? Whole trip? It could be a lot of things...sounds electrical if it is that intermittent (fuel pump relay perhaps?).

__________________
TC
Current stable:
- 2004 Mazda RALLYWANKEL
- 2007 Saturn sky redline
- 2004 Explorer...under surgery.

Past: 135i, GTI, 300E, 300SD, 300SD, Stealth