That ruined my evening. I was hoping I could just replace the tumbler or the key.
If the tumbler isn't turning, you probably can. If it was turning and there was an occasional time when the starter wouldn't engage, it may be the electrical component on the column. If you replace the tumbler, be sure you get one for an 88. Keys and tumblers are different on the 88, though earlier years will work. The slots on the sides of the keys are located differently. Just makes it easier for anyone getting a key made in the future. Wouldn't want to be searching for a key blank for an 88 when the tumbler is for an earlier year.
I have a similar problem with my headlights. The low beam sometimes won't come on without activation several times with the column lever. They even just go off sometimes while driving. Again, it's a switch that's located on the side of the column underneath the dash.