When I get up to 55 and start excelerating my car vibrates. But when I let up on the gas it's fine until I push the gas again. Then when I'm braking it shakes too.
My car has 176000 miles.
My car has a manual transmission.
The vibration and shaking when accelerating may be a transmission shift issue or the engine is misfiring under a load. The shaking when braking may be due to warped brake rotors. You should have the computer scanned for misfire or transmission codes and have the codes diagnosed. The brakes should have a complete inspection to see if the front or rear brakes are causing the vibration when braking. I would recommend having a mechanic like one from YourMechanic diagnose the problems for you.