1989 Plymouth Horizon, 30,000mi. Conking out aft. Starting

Help. Elderly mother has a 1989 Plymouth Horizon with approx. 30,000 mi. On it that recently had a tuneup with about 3 sparkplugs & wires replaced. Since the tuneup; I took the car for a longer drive. It sat outside (very mild weather) for about 2 1/2 hours. When I went to start it, it started right away, but conked out immediately at least 2-3x before it continued to run. Didn't do this prior to the tuneup. Any suggestions or advice on why this would be conking out when starting it? Thanks.