I had the exact same problem this week when I took mine out of storage and it turned out to be a bad spark plug. I replaced all the plugs with TR6's at 0.038" gap and it purrs like a kitten now!!!

 

Carb cleaner is fine. I usual hold the port side up fill it and work the plunger back and forth with a pencil. Then I turn it over and shake the residue out let it dry spray a small shot of WD-40 in it the shake out the excess and your good to go.

Peace, Suavy

 

How did you plug go bad while it was in storage? Im having the same problem right now but it only does it at 35-45 MPG w/ OD off. Actually I never had the problem with the predator tune, it jsut started when I went to the stock tune. Im not showing any codes either