Problem with GTA San Andreas for PC Custom Cars! They wont go away!?

I installed GTA San Andreas... it was fun for awhile, but starting getting boring so I decided to add some custom cars/weps/etc from downloading them offline. Well, I think I added one to many (by swapping their info and models with default cars) and the game started to lagg every 5-10 min.

So.... I reinstalled GTA:SA, thinking that the original cars would be back. After the installed, I open GTA. The custom cars I installed were still there in the files. Doesn't make any sense. I reinstalled GTA a few times more and still the custom cars are still there. It doesnt make sense because when I uninstalled, I made sure that any GTA data was gone, but some how something stayed the same.

Now everytime I play. I see the cool custom cars, but the game laggs horribly every 10 min... Anyone have any suggestions that could find out why the car models are still being loaded?

Oh, and I after uninstalled, I searched through every GTA file I could find. Like the User Files in Documents I deleted. So could anyone please give a suggestion so maybe I can play my game sometime soon?