i have a 2003 sle that has a death shake at speed around 75 or so that seems to go away to co9me back to get worse. ive checked over the entire car and replaced some parts as well. everything is tight, tires were balanced and balanced again and they balanced out according to the machine but still has this issue and the alignment was done and is right on the money. what the hell could be causing this? i know there is the tsb for control arm bushings but how do i know if it was done already as im not the first owner. please help.

You can have the dealer run your vin to see if the car was ever repaired under the TSB.