I have a 156 1.8 TS from 1998 that wobbles/vibrate when accelerating 2000/3000 rpm and especialy when turning right.
I checked everything and noticed that the 2 drive shafts dont have any play, the half shaft (extention of de right side that has a support bearing and that connects to the gearbox) had a lot of play and was replaced by a used one in a very good condition, also the left upper suspension arm (aluminium) had the rubbers shot (lot of play) and was replaced today.
The tyres are brand new and the car had that problem before replacing the tyres.
The problem is still there.
If I drive fast on the highway (120 to 180km/h) I dont notice vibrations.
If I drive at normal speed (40 to 80km/k) on a twisted road, turning left it does not wobbles, at straight little wobble, turning right a lot os wobble.
The wobble is noticeble at low rpm but with the engine/gearbox on load, for exemple going up the road and turning right, at 40km/h on third or on fourth gear and trying to get some speed at that gear and rpm. (without changing gear)
Its almost like having an oval tire.
I´m really lost on this...