1998 Infiniti I30 Problems

[Tidler]

I currently own a 1998 Infiniti I30 auto. with 252,000/km. For the past year or so that I have owned the car I have noticed when the transmission is to shift any where from 40-60/km and I quickly let go of the gas pedal quickly right after it shifts the car kinda jerks or studders a bit then goes away, and same thing happens when i place my foot back on the gas. Almost has the sensation like im driving a standard. When you press the gas a bit firmer from shift-to-shift the car seems to shift fine and smooth without any symptoms. There seems to be slight hesitation to upshift in some gears aswell mostly 3rd and 4th. transmission fluid was just replaced and still same issues. Check engine light is on but the code reads Evap System Pressure Sensor which ive been told by infiniti will not cause these issues. Oh and this happens when the car shifts through most gears at 2000 rpm. When its shifting through gears at let say 2500 rpm it shifts smoothly but still can occasionally studder if I remove my foot off the gas quickly at 60 and 80km. Some Help please thanks guys!!