This sounds like just the problem my mother is having. She got hers in 1992 also (not sure of the model #) and has replaced many ignitors. This winter has been a nightmare. Two thermostats replaced, many visits by HVAC repairmen and finally the owner of one of the places told her it was the board that needed replacing. Quote is $519.
At this point, she has spent more on repairs than half the cost of a new unit. According to Consumer Reports, that's the time to invest in a new furnace.
So we are looking at the Carrier 58MXA (WeatherMaker 9200). Quote is $3035 and AFUE is 95.5%. Go top of the line for reliability and quality.