I had this problem pop up about a month ago, and it seems to be happening more and more often now. I'll be driving along, and all of a sudden the horn will honk, randomly.
Sometimes it will stop there, other times it will honk again a few moments later. Sometimes its a short honk, sometimes its a little longer. When it happened last week, I had an issue with the factory key fob working right after this happened. Since then the key fob has worked on and off intermittently. The battery in the fob is new as of this spring, so I don't think it needs to be replaced yet.
I did some searching, and couldn't come up with anything. Anyone else ever had this issue before? I'm wondering if there is something wrong with the security module? I think for now my plan of action will be to turn off the factory alarm system and see if the problem goes away, but I'm hoping someone here has a more specific answer on what could be wrong.
Oh and the car is a '97 LSi if it makes any difference.