2000 Saturn LS2 quits after start -have codes

[oakes_nate]

2000 LS2 with approx 90k miles.
Car will start and run a short time then die. First quit when going downhill coasting would not restart. Started ok next morning then died again.
Local garage checked fuel pressure, 41 psi which is within range. Garage did not have access to Saturn's engine code information.
Codes set with no info available are: P2B01, C1618, P1829, P2903, P1780.
Other codes are: P300A, random cylinder misfire and
PO621D, generator L terminal circuit
Nearest Saturn dealer 70 miles away, local dealer recently defunct!
Garage will help me out as they are able.

I expect a sensor problem or possibly an electrical system problem but not sure where to start. Alternator output checks ok.
Any assistance welcome.
N. Oakes