Is it a problem with the GTA IV servers or are you maybe having a problem with your PS3 on PSN?

Yeah check your other games just to make sure it isn't something on your end. With all my complaints about GTA IV, I have never heard about there being any serious connection problems.

Well if you were playing another game and not having a problem then obviously this is not an issue on your end. I had no idea that GTA IV servers were problematic.

There are sometimes connection issues with games concerning your server type. Most games work fine but some have issues either cos of an update or the current state of their servers. Basically my understanding is if your server type can't stay connected on its default setting you need to change to proxy server or something.

Also if it only happens in some matches on the game it can be to do with another players server. Some matches I played I'd lose connection because the host or another player causes a conflict. Another time Me and my friend played on a game I started and the first player asked to add a friend. My friend did so and then he was kicked after the guy left. I hadn't voted so it was obviously a technical issue to do with the player my friend added.

You may need to open more ports or do something called port forwarding, but now I am pretty much talking out of my ass. This is something you should probably also ask in the Genital PS3 forum as well as here, because maybe your router is set to block out certain things it shouldn't be blocking. Again, the guys in the PS3 forum as well as the PC hardware forums would be able to tell you a lot more about this I would imagine.