my blazer started out acting funny earlier this year. I would put it in reverse and it would feel like it didn't really want to go backwards, like it was a little bound up. I never had to really had to give it alot of gas or anything. During Spring Break we took a trip and we parked at a slight incline and when we put it in reverse it started to shake (vibrate). put it in drive it didn't vibrate. with in a couple of weeks it was vibrating in park, drive, reverse. We gave it a tune up as the vehicle is notorious for needing one every spring when it rains alot. No luck, engine still ran bad. Was parked and put in reverse I heard a lod thunk and than Blazer got really loud Catalytic converter broke off at the clamp where it mounts to the y- pipe. We recently replaced plugs, wires, rotor and distributor again, it ran fine until it got warmed up, cleaned EGR Valve and ran seafoam through it. The engine miss is gone and it still seems to be okay. We still have the vibration even if it is in park. The vibration is in steering wheel floor boards, making everything rattle and shake inside of it. Torque converter did shutter when it shifted in and out of overdrive when under load ( up hill, etc...) does anyone have any advice. I don't have a lot of money to pay a shop to go through truck and find problem. Husband is excessivly p.o'd about the whole thing. Laurie