Can I use a 2004 g35 coupe Transmission on a 2005 g35 coupe?? Both cars are RWD. After putting the 04' transmission in the 05', the gas pedal is having issues. Whole car was lifted, oil was put in the transmission, everything was working fine, put her down and the car won't accelerate. All the connectors are the same, and gas pedal was working fine at first, but then just stopped. Car turns on and idles fine, just the gas pedal/accelerator isn't working anymore. Could the 04' transmission be the problem for this happening? Anybody have any suggestions, or know how to solve this???

I believe you will need to take the car to the dealership to have the TCM and ECU 'married'.
Some of the early '04 cars (and all 03's for that matter) have the TCM located in the passenger side kick panel, while late-04's (and all 5AT cars from then on AFAIK) have the TCM physically mounted inside the transmission with the valve body.
Since you say all the connectors matched up, I think you just need to have it programmed is all (hopefully)

I have swapped RE5 transmissions with the built in TCM and haven't had any problems. They are not married to the ECU. The only time you may have a problem is if you get a new valvebody / TCM from the dealer because they are blank and need programming. Sounds like the op has other wiring issues.

Does the engine rev up when you push the gas pedal or does it not go past 2500rpm?