1994 Buick Park Avenue Car stops running

I have had a problem with the car turning off for the past couple of weeks. I will do my best to explain what is going on. When you are driving in town the car will just die. If you have the radio it does not affect the radio at all. The battery guage will pop back and forth right before it dies. I will put it in nuetrul, start the car, put it in drive, and all is fine. It doesn't happen just when you are turning, coming to a stop, and at a light. If you drive it on the highway it drives fine. Does not die once. As soon as you get into town and come to a lower speed it will die. I parked the car over the weekend and come Monday morning it ran fine. Never died once. But come Tuesday it died several times within the 5 minute drive to work. The check engine light is on but will sometime shut off. We have had a fuel volume test done. They said the fuel pump was fine. We have changed the fuel filter and air filter. We have had the battery, battery cables, and alternator checked and was fine. The garage done a diagnostic and said the Throttle Sensor was bad. But others have said that they don't think that this is the problem. I have some suggest a coil or the Electronic Ignition Switch. So I have everyone stumped. I hope that you guys can help!