short problem in my Tahoe

I have been blowing my engine fuse. Mechanics have told me that they think it could be the cam sensor. If it's not good then why won't the computer tell me that. I keep replacing the 20amp fise and when the car is on it runs fine. The fuse only blows when I shut off the car and leave it sitting for a while. If I continue to drive without shutting off the car it wroks fine. does anyone have a clue, or has anyone else experienced this.

many items on the same fuse check MAF sensor and O2 sensor wires
ignition wire is pink-black