See i have a problem, my guitar is out, but see it is in tune on the open strings but when i start playing past the twelfth fret it starts going flat.. Does any one know what is wrong??? i have an ibanez GRG272
dude i have one, thats how i know its out.. and it sounds bad..
maybe you need an adjustment to the neck
Holden Caulfield is a friend of mine.
We go drinking from time to time.
How do i intonate it... and isnt intonation for string hight?? and fret buz
no. intonation is to adjust the length of the strings to have right pitch when 0 fret picked, 12 fret picked, and other frets picked.

look at the "Setting intonation" section on the link i posted.
Call me "Shot".

ShotRod Guitar Works

Custom Hand-wired Amplifiers and Effect Pedals.

Est. 2007

Source to everything I say about Guitars, Pedals, and Amplifiers: I make them.

UG's Best DIY PedalBoard
You should take it to a guitar store, and let them do it for you, but ask them what they did and how they did it though, so you'll know how to fix the intonation from then on.
Ibanez SR505
Ashdown ABM 300 EVO II
Epifani UL410
How old are the strings? I can't stand the sound of old strings. One of my first guitars was an ibanez and I thought the same thing a couple times - that the guitar would just not tune. After I would replace the strings, I would find it sounded a lot better. Just my opinion