Keep going it will I promise. The 3.5 motor is a strong performer. One of the Wards top 10 for many years. And one of the best engines of all time. You have to keep giving it gas until it goes up above 2.5K RPM. It will.
Go out and get on a highway or interstate and put the peddle down to the floor. Then you will see it jump up. You can push it down slowly to get a feel for when it will jump up in RPM.
I don’t know what you mean about the jerking. Sorry I don’t understand what you are saying. Can you describe it again?