i need help with my celica

its a 1997 celica st and when i go down the gears and up the gears and accelerate all round by the suspensions make knockin sounds.

and when i put my fut down and touch between 60mph-80mph the whole car vibrates and steering wheel shakes like any thing iv taken it to garages and they cant find any problems.

and i have also a a power boost valve to fit but i dont no what the psi should be for the fuel to fit it.

any body help please cheers

aaron

check your motor mounts?

i would take a video, what sounds like a knocking noise to you might be a flapping or metallic tapping noise to a seasoned mechanic. i would jack the car up put it on jack stands, check the wheel bearing play, check your balljoints,tie rod ends, manualy turn the wheel(key in ignition to keep it from locking) and check to see the shocks are turning nice and smooth. check motor mounts,check drive shaft damper( its on passenger side right below power steering). diagnosing these sounds is such a pain, i got a flapping noise i can barely hear when its just my 120lb behind is in the car but when i add another passenger i hear it louder at around 50mph and above. checked all suspension looks and feels fine i know my shocks need to be replaced.so i know how it is to have an annoying noise that you cant chase down, i even put it up on jackstands and got it up to about 40 mph and no noise or anything,but good luck trying to diagnose it seems like some here wont help diagnose problems....

Check your lug nuts too. Shaking at speed is most likely just unbalanced tires and probably unrelated, but don't count it out just yet.