Nissan Altima 2002, 2.5S strange issue

What happens is when I put brakes at signal lights, then release the brakes and press on accelerator it doesn?t move forward, break will get released but car doesn?t move forward at all.

I have to put it back to parking gear, then put it in to drive, and then it moves forward.

We have shown it to two mechanics both couldn?t figure out the problem, one just did the engine tuning and thinks that will help.

Please help!!

Does the engine rev up when you press the gas pedal? Or what stops it from moving?

Checked the transmission fluid level? How many miles on car? How long since tranny fluid was changed?