I have an 09 Dyna with a Rinehart 2 into 1, ness big sucker, and PCV. I have run it about 1000 miles with no problem. Yesterday I crank her up and she immediately starts surging and hunting. By this I mean it seems that a sensor is not working. The bike is new and all connections are fine. It accelerates great, but when you hold a steady speed or let off a little, you feel a surge. Sometimes it will rough idle. This happens about 30 minutes out of an hour ride. Fuel mileage is down too. I am downloading codes today. If no easy fix, off to the stealership Monday.

 

Check spark plugs and wires

could be your map

I'd say fuel pump, but sounds like you're riding with less symptom then I did.

Just throwing ideas out there!!

 

Sounds like classic 'water in the pc/ecm connection'.

 

Mine did the same thing. The dealer found a broken wire to the fuel injector-no charge and out of warranty!

 

Just linked this to another post just now. Here it is again in case it helps. This is probably what Motosurf's looked like.
https://www.hdforums.com/forum/dyna-...you-later.html