I had some trouble with one last summer.
It turned out to be a bad relay. One of the 2 that are attached to the ECM.
I called Trail Tough and Brent suggested that one was bad. He says over the years, moisture gets in and the contacts get a little dirty, rusty, whatever, causing them to stick. When they stick, they will cause a short. Blowing a fuse.
I replaced both for good measure. I was able to get them at a local GM Dealer. I have a friend and I was able to get them for $27 each. You might try there.
Also, this summer I had the same problem on another Tracker.
This one turned out to be the O2 sensor was bad. If I unplugged the O2, it would run, drive, start and everything, just fine. When it was plugged in, it would start idle a couple of seconds and pop the FI fuse.
That one turned out to be an easy fix. Install new O2 sensor.
One other thing to check is the grounds on the disty. They get weak over the years too.

These things will made a person real mad, real quick!

It will work out though, be patient.