I have a 1997 Z28 with power locking and when ever i hit the lock button from my keyless remote, the horn makes two normal sounding chirps, followed by two honks from the horn. It is really annoying and would like to know how to stop it.

 

The two honks from the horn are what our cars do when you lock them using the remote. The two "normal sounding chirps" are probably from an aftermarket security system installed by a previous owner. Find out what kind it is, look up its manual online, and find out if you can disable the chirps. If you can't, just remove the aftermarket system from the car.

Good luck!