If it continues to do it, you might want to replace the TFI module that bolts to the side of the distributor (where the big harness plug goes into). They are notorious for going bad (especially when they are hot, after you've been driving for a bit). It takes a special tool to get the TFI off, but its small and most auto parts stores should carry it.

It also may be the PIP (Profile Ignition Pickup). Its a little module inside the distribotor. Both are pretty cheap to replace and common problems.