check the motor/transmission mounts. The front drivers side transmission mount on my 91 has been broken for a couple of years. Ive tried fixing it but it keeps breaking.
the shuddering could be caused by the engine moving too much during a hard acceleration. Ive trained myself to be very light on the gas to avoid any engine bumping.
to check it, put the car in drive, hold your left foot on the brake and pulse the gas pedal. have someone look at the engine (hold the brake hard so you dont run them over
) and have them see if it moves alot. mine moves about 3 inches or so which is terrible, it should only move less than an inch. im just too lazy to try fixing it again. im more concerned about fixing the suspension now.