Shifting issue

My car started acting up a couple of month ago and I do not feel smooth shifting anymore while shifting mainly from first to second and the car jerks and the rpm's does not act normally and is not increasing or decreasing steadily.
The weird thing is that, for the first time in summer when I turned the air conditioner on and after fifteen minutes of driving, the shifting and the rpm's were acting normal and very smooth and the gas pedal became more stiff (that I really liked the stiffness, it was enough). But that did not last too long, and I still have jerky shifting even after I turn on the air conditioner.
I do not think this is a solenoid problem, because I have scanned the car and did not show any faulty codes and the transmission fluid looks normal.
Any idea will be appreciated.