Q: Car will not pick up until easing off the gas pedal, Infiniti G25

Instead of using a conventional mechanical throttle, your vehicle uses a "drive-by-wire" system. This design, throttle position, and accelerator pedal position are relayed to the control module via dedicated sensors. The control module then uses this information to control a throttle body mounted motor. The motor opens and closes the throttle as needed. Nissan recalled close to a million vehicles for problems with the accelerator position sensor. This may be your problem. I suggest you have a professional, such as one from YourMechanic, diagnose the acceleration firsthand to determine the cause of this.