Here's my recipe: http://blog.streaminggourmet.com/2009/10/23/ultimate-pumpkin-bread/
I added an extra egg to the last 1/3 batter and the bread didn't collapse as much, but it also wasn't as good as the original bread (that did collapse).
I wrote the High Altitude Baking section of the Bakers Dozen Cookbook because I've long lived at altitudes which presented challenges. Definitely add the extra egg, and also increase your flour by 9%. Most important, decrease your leavening by 56%. Yes, 56%. At elevations above 2000 to 2500 feet, there is literally less atmospheric pressure bearing down on the surface of what you are baking. This causes them to rise right before your very eyes, then fall dramatically because the protein doesn't set up in time to hold that risen state. By increasing the protein and decreasing the leavening, you meet in the middle and your pumpkin bread should be lovely.
Okay, now for the stupid question ;) What is the leavening? Baking Soda? I'm clueless. Sorry.
Oh, I'm so sorry! I looked at your recipe, and noticed that it calls for both baking soda and baking powder. Baking powder is the only one you need to adjust because baking soda is proportional to the amount of acid present, and pumpkin purée is slightly acidic. Reduce your baking powder to 1/4 teaspoon, add an egg, and increase your flour to 3 1/4 cups (and use a heaping 1/4 cup at that).
Yeah, so this is how they turned out... now what am I doing wrong? Seriously confused! :(
Also I am at 6850 ft.