Hey my fellow trailblazers I need help big time. My trailblazer, an '06 4.2 lt, is acting up, and I have no idea what the problem is. When I start driving highway speed, my whole car starts to shake inside and out, and i feel the brake pulsate when I press on them, also does this when i reverse sometimes. Also I hear a strange sound coming from the wheels. Now I took my truck to the dealership, and a regular mechanic I go to. I fixed a front wheel bearing, a u-joint passenger rear, didn't help. I changed my struts and shocks, also my rotors, and brakes. Tidbit: when i changed my rotors and brakes it helped considerably, then the way it was before, but it is still doing the problem above. One of my tires, kept losing balance so we put the spare rim no go. Dealership, and the mechanic, don't know whats wrong, and im outta money to keep fixing even though they were needed, to keep fixing something that's not stopping the problem. Please someone help, any suggestion or did anyone have a similar problem? I love this truck, but this problem, is making me want to get rid of it, going out of my mind!!!