1997 Chevrolet Blazer 4 WD mileage: 70,000. I checked the previous questions and maybe the solution to my problem is worn CV joints, but who knows? The truck is in excellent condition. The problem that I'm having is at high speeds say around 70-75 mph. There is a vibration in the front end with a little shimmy in the steering wheel. The vibration causes the passenger seat to shake a little, and I can feel it under my feet. The truck is in drivable condition though. The vibration is on and off and was not present when I bought the truck new. The truck has not been into an accident at all, has had several alignments; tires balanced over and over, front end checked (everything is tight) upper and lower ball joints replaced on both sides, etc. After having the ball joints replaced, it cured it a little but the vibration is still present. I know of a few customers that are experiencing the same problem. I've been trying to figure out what's causing this to happen. The front end has been looked at quite a number of times and everything is tight. I've put a lot of money into trying to fix the problem. I don't want to spend any more money until I really find out what's going on.