Dan, this is one of those "for what it's worth" stories.

About 30 years ago I flew a Mooney ranger that was pulled around by a
normally carberated engine that loved to develop carb ice. The first
clue it was happening was that the EGT began falling really fast. Carb
ice drives the engine towards a richer mixture.

The same thing may happen in your airplane. If it does, include the EGT
in your instrument scan when you're at cruise. I was amazed when I
started doing that how often a 50 degree drop in EGT happened, and how
often it was recovered by yanking on the carb heat knob.

I'm glad it turned out OK -- angel flights should get lots of second
chances.