What could cause a 93 Grand Am to shake once you get to a certain speed and then hit your brakes? It does the shaking thing not only when you push on the brakes but when you are going maybe 50-60. Also the oil pressure gage goes really high when you push on the gas is this normal?

Rotors are warped need a GOOD brake job!

Ball joint, tie rod end, cv-boot, cracked axle, warped rotors,etc, all good posibilities. Have ur rotors turned (do not pay more than 15 dollars each to be turned) shop around for them too, u may be able to buy new ones for less than getting them machined, & get an alignment done. When the mechanic does ur alignment, ask him to inspect all ur chassis parts & ur axles & boots to be sure of any issues. The oil pressure guage is another story. Have a diagnostic check done to see what codes r being thrown. This will cost no less than 65 dollars, fair warning. Good Luck.