Same here i cant get it to work...i think there a fluke...

on the xbox 360 version of project 8 i think th there is no cheats for perfect grind, perfect manual, no gravity those kind of goodies. this is because there are achievements and if there were codes for that kind of stuff then the achievements would be too simple. i think that there should be codes for this though because it takes the fun out of the game. i mean who doesnt want to grind or manual for a thousand feet and soar into the air about 1500 feet. its fun but looks like we'll never get it on 360. i guess the only way to have cheats in the game is to play it on a different console.

I have a 360 also and it doesnt work either and i cant get the 50000 point combo on mike
v'se demo and i am rank 90. One code that does work is needaride which gives you all decks
unlocked except gamestop and inkblot and all boards are free

The cheats have worked for me. All the perfect ones (Grind, Manual and Moon Jump). This
was when I got the game. But after I completed it I left it for a while got a new 360 (Red
ring of death ;[). I started playing again and now the cheat codes don't work. I have had
to do updates for the game, maybe thats it? :/