Ok, so again i took the tailgate apart and found that the springs that release the tailgate were kinda weak, I through silicon grease at it and pulled the "rubber" bushing out of the hinge and massaged the silicon grease into it. cleaned out the hinged areas and now it drops fast and every time. I called Chevy and a technician told me that you need to use silicon grease. Do not use regular grease, from the factory they "use" silicon grease and regular grease would not mix well.
Thanks for all the help.