Okay, so for a while now my PS2 has had this apparent graphical problem. Many of my games have this problem in which these odd lines are projected upon many in-game walls or other solid surfaces, including the ground and usually the sky. These lines tend to flicker wildly whenever the game's camera is in motion, which is really what makes them noticeable. Also, in a game that has a day/night cycle, the sky usually does this strange flashy thing during nighttime.
The game that has it the worst is GTA San Andreas. It's just everywhere in that game and it's extremely noticeable. At first I was thinking that this was just a sign that my PS2's graphic card was starting to go bad, and that wasn't too surprising since I've had it since 2006. So I figured that if I buy another PS2, I wouldn't have this problem anymore.
Well, I was wrong. I ordered a new PS2 off Amazon and San Andreas was the first game I tested. To my surprise, the same thing still happened. I'm really confused. Is it possible that this graphical problem was actually imprinted onto my game discs from my old PS2? It's not my TV either, I've tested more than one.
It's more likely that this is how the game runs on the ps2. The lines you were talking about that flicker when the camera is in motion are called Pixelation Lines, they've been on almost every game for the ps1 and ps2, and I've seen them on Fallout 3 for the 360 and ps3.
As far as San Andreas goes, its a large game, its strenuous on the console. Also youre playing a ps2 so I wouldnt expect great things from it. If you dont want minor glitches an pixelation lines I would get a PC and a good graphics card, the ps2 is an older console and has an older graphics card/processor so it just plain wont run as well as a basic computer with a graphics card in it these days.