I hope this isn't a repeat post but I need help! I have an 04 heritage efi and it is running horrible all of a sudden. It coughs and chugs and misses really bad so far that it's seeming to run on 1 cylinder. I have replaced plugs and wires on it. I ran some injection/system cleaner through it and didn't so I sucked all the gas out of the system and put new in and didn't get any better so if anyone can help I would really appreciate it!!!!!!

 

How is it at an Idle? Is it running fine? Could be as simple as a clogged fuel filter.

 

Are you showing any codes?
Check the connections on the ECM and the BCM.

 

Crankshaft sensor?

 

The idle rolls up and down and caughs out of the air cleaner I'm surprised there are no codes in the system the fuel filter is only about a hear old.

 

Mileage? You could have pinholes in your internal fuel lines. Does it happen when the tank is full? Or only when less than half?

 

just turned 20k it initially started when the tank was under half but now it does it constantly