I have a '91 Buick Regal, and the check gauges light comes on, and then my car shuts off. This occured while I'm at a complete stop, or was driving slowly during the first couple days, and now it's happening even at 40 mph, so of course I've discontinued to drive it. Any idea what it could be?

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On those often either a bad ignition control module or weak fuel pump.. Both can be tested.