Stupid thought, but is it possible that the exhaust is plugged? I had a Triumph many years ago that this was the issue on with similar symptoms.

 

dont think a fuel controler will fix a problem,may make it worse. try cleaning or replacing the iac (idol air controler motor)its cheep.next look at the tps adjuster screw,looks like an idol screw but its not,it should be locktited from factory if its loose that would mean previous owner tryed to get the low idol sound,the screw is adjusted to the signal sent out by the tps,if its not right it will do what u are describing.

 

Cleaned off the iac, and pulled the tps and cleaned as well, could not see any adjustment screw like a idle screw. The bike ran better after this and I took it for about a 12 mile ride, I then after letting it sit for a while got back on and it seemed to throw a code and the bike went back to the same problem again. Is it the iac or possibly a new tps or fluke thing