I cant get my stin ray to work with my ps2 gran turismo 4, Why?

Here you go:
http://www.ign.com/cheats/games/gran-turismo-4-ps2-489327

Yes the problem is the laser. It's on its way out (and is almost completely out). You can find a new laser for the 77001 console at the following page. They also sell the completely laser assembly which includes all moving parts in there:

http://store.richspsxparts.com/slpvps2lahef.html

aa banish ???????????????????????????????????????

your games are dirty.. since you have a slim it is easier to clean your lcd.. go on youtube how to clean lcd on ps2 slim

do you have a slimline ps2? the problem is more than likely with the drivers in your console. do all your other games work just fine? only gt4 thats not working? gt4 is a duel layered disc unlike most games.
my console won't play it either. plays all other games, even ones on the blue discs wiv no problem.

must be use game

I've encountered similar problem with my PS2. I really can't play the disc that I bought. There might be some burning problem that difficult to read by your PS2. What I did I've tried to copy it and burn in to a better DVD disc and it works. Try it.

over use of your system your ps2 needs maintenance and cleaning remember the more you play your ps2 the more its like a car going up in milage

If this is Gran Turismo 4 you are talking about, then if you still have the save file on your memory card from Gran Turismo 3 you can transfer your credits and all your license data over to Gran Turismo 4. In Gran Turismo 4 go to Home>Status>and it should give you an option somewhere on the bottom on the screen to transfer data, I think you press the square button. It has been a while since I've played Gran Turismo 4.

Generally the game options must be set to use the wheel instead of the standard controller. In Gran Turismo 4, for instance, there is an options screen where you can configure the steering wheel.