Geez Tim, Honda drivers around here NEVER use their signals, I just assumed it was an economy move on Honda's part. If that's as typical around the country as here that might explain why no one has the answer.

Okay, okay, ten year old car here. Could it be this is a sign of wear? I don't have a wiring diagram on one of these, but if it takes it's signal from the distributor as the aftermarket ones do you may be seeing evidence of some slop in the distributor drive system e.g. gears, belts, whatever. Or does it read from a sensor on the crankshaft snout and there's something at the sensor that's interfering with the signal?