just bought car with 146000 miles-well maintained-its cutting randomly when driv on 1995 Buick Regal

it needs a little gas while starting, then service engile light comes on after a few miles and it chugs out randomly in speeds and gears...the camshaft sensor just replaced by old owners, (said the car died in town and had mechanic do it for 200. only other issue is ABS sensor is out on front right tire. only driven 500 miles since i bought--also had to fill up coolant and tranny, but doesnt seem to leak at all. is clean and was maintained by older couple-old neighbors-but sat mostly last couple years...please help with any advice, (oh it died once after drive when i was parking as well--ty

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