Hi Scott: I recently had a similar problem, and it turned out to be the gyro. Depending on the age of your gyro...and the updates that have been done....my quotes were $3500 and up for an overhauled gyro. New was over $5000. The Sandel that Zach mentioned was over $5000 and had some other installation complications that were going to bump the price up even more.
At those prices I started thinking Aspen and replacing the gyro and the HSI panel instrument, but it was during the busy season when I needed the airplane and my experience with radio/panel changes has been they always take lots more time than anticipated. I also had some concerns about abandoning the steam gages that I have looked at for so long.
I fortunately came across a used replacement KG102 for $1000.
It had all the updates and a 30 day "buy and try". I decided to take a chance on it. So far it has been perfect.
Bottom line.....if you want an excuse to install a glass panel, you have it.
Warm regards, Al Powers
PS. It's a cold, windy, wet day in Seattle, and reading of your plans for the Bahamas makes me envious. ahp