Mine did it for about 2 years. I would be at a red light and it would honk, people would look around and I just waved at them and grinned. The speedo and other gauges would go haywire also. It has something to do with some wiring under the steering wheel airbag or the BCM wiring in the passenger footwell area. Go over to LS1GTO.com and search for "phantom honk".