I have a 2007 streetglide with 37000 miles. some times when engine is under load like up hill in 6th. gear the engine will miss or back fire. possible coil? how often should coils be replaced?

 

Check that the plugs are the correct spec....this bike has ion sensing knock detection...the wires and the plugs need to be jiving....to me....it sounds like a spark plug wire breaking down.....I am old skool though...