['Vette Nerd]

I was looking at one of my SEs last night(this thing's had steering trouble for months already) and I noticed that the front left tire would work okay for a little while and then it becomes sluggish and the SE drags it around, causing it to stop turning left and start swerving, only going straight or right. I can't figure out what would cause the tire to stop moving, but I really need some expert help and I really don't feel like buying another one! And believe me, I've tryed searching it and couldn't find anything close to this kind of issue!!! HELP, Please!!!