Q.heuchera coral bell plant
For the first two years my heuchera plant(coral bells) budded and then flowered. For the past 3 or 4 years it budded but never when to flower. This year I did NOT fertilize it at all to see if maybe THAT was the problem. It has new shoots with buds again this year and I would really like to see the flowers once more. I have it in a shady some sun area. What could be preventing it from flowering?

Verify the plants growing conditions with the information in the article below.
https://www.gardeningknowhow.com/ornamental/flowers/coral-bells/coral-bells-plant.htm
You mention that you held back fertilizer this season. If the soil has too much nitrogen, it will inhibit flowering.
You could certainly have the soil tested to determine if this is the cause.
A boost of phosphorous can help get the plants flowering. Bone Meal is a good way to add phosphorous to the soil
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/bone-meal-fertilizer.htm