850 shakes badly at high speed

Henry · 2004-01-29T00:28:16+00:00

Sort of a duplicate post here but wanted to flesh this issue out.My car, an '96 850 turbo sedan runs smooth as butter at 100 mph.Absolutely smooth, you could finish the decorations on a wedding cake inthe back seat.But at 110 it begins to shake roughly, almost violently.1. Tires are V rated Michelins, with about 7k on them, almost new.2. Car has been perfectly maintained. That means fresh fuel filter,etc,etc,etc, I even put new front ball joint/control arms on at 100k justfor the sake of it. The car has 122k on the clock and runs like new.3. Stock ECU and exhaust and air intake.4. Tranny serviced (despite maint recommends) every 20k miles.5. Tranny shifts like very smooth, kick down prompt and sure. Lock outgood and easy.6. Never had anything but Mobil 1 5w 30 in it.Ok Guys, Got any ideas?PS I don't usually drive that fast but had the occasion to (was passingabout 5 cars at once and went from 60mph to 100 in about 3 seconds, feltgood and with smooth open road for miles ahead I thought I'd air her out alittle, till she got the "shakes", that is.Thanks in advance.Hank