Newbie here, dunno where to post this, hope somebody will cross-post this key discovery for '98-'04 Regal GS with dead-engine syndrome in the proper place:

Based on info on this group and others, after my '98 GS w/197,000 miles died beside the road, we found a dead Ballast Resistor, installed new unit per Buick recall, now screwed to the center of the firewall behind the engine with a new wiring extension zip-tied to the frame brace over the battery. Thought the prob was solved but over several months it continued to do the same thing, sometimes recovering after cooling down, sometimes staying dead. Would run a few seconds and die. So:New fuel pump & filter, ignition sw, both FP relays, new ign module, new crank sensor (it WAS bad, so there were two failures), but finally inspected the wiring CONNECTOR that went to the original ballast resistor behind the headlight...duh! It was as corroded as the resistor! Nobody had thought to check that. The rubber weather seal on this connector was also scrunched, so water got in very easily. Cleaned it with contact cleaner, did a bit of scraping w/dental pick, bit of dielectric grease as I plugged it back together, car started immediately and actually seems to run better, probably does with full voltage to the fuel pump now. One consolation is that I now have many new sensors and engine accessory parts that should keep it running for a long time.