cruising down the road yesterday when out of nowhere my bike starts to backfire, hiss, cough. any ideal where to start? checked spark and it is good. stock bike with efi, v/h pipes and screaming eagle upgrade installed by dealer.

 

My bike ices up in cold weather, acts the same way. Let it set warms up the carb. and it's ok for awhile.

 

That's a typical symptom of the fuel line in the gas tank having a small hole in it.
The line/hose rubs against an internal weld and eventually wears a pinhole in it. I would start there. You may be able to hear the leak though. Turn your ignition on (don't start the bike). You should hear the fuel pump run for a couple of seconds and then stop. If there's a hole in the line the pump will cycle on and off trying to keep the fuel system pressurized. You may also be able to hear a leak by removing the gas cap and listening for a hissing sound coming from the tank.
This is a picture of the line out of my Deuce. It took me about 2 hours to change the line.