1986 Plymouth Reliant stalling

Engine Performance problem
1986 Plymouth Reliant 4 cyl Front Wheel Drive Automatic

sudden loss of power while driving like engine wants to stall or cut out then quickly resumes normal running, engine stalls at red lights, loss of power indicator dash light comes or periodically. We have a new distributor/rotar/plugs & wires/air filter on the car. When it is running normaly it runs very well. No cylinders missing or anything of that nature. It has been suggested to me that it may be a "speed variance control sensor" on the tranny that may be the problem. Any help is appreciated, Thank you. Bruce.