cut and pasted from post on IMOC, as I know a lot of Supra owners traded up from MR2's and there's a lot more people on here than on the MR2 forums:
Basically the rear of the car feels like it is 'washing out' and under acceleration, the car feels really unstable:
About 4 weeks ago I was on a trackday and the car ran fine all day and then on the last session something didn't feel right. The car felt different immediately and I spent 3 laps trying to diagnose the issue with no luck.
Recalling that at the MOT I was told my track rod ends were on their way out, I had a local garage replace them and I also replaced the speedo converter/delimiter to one of Stefs. Took the car out and it felt pretty good just driving around normally.
I have since replaced the stock turbo suspension with BC coilovers and again, after a bit of playing around with the settings, the car feels good under normal town driving.
However, on hard accelerating it feels really really unstable. Once at speed (eg 70mph) it's fine, and cornering seems fine, but I need to back off when accelerating as it feels like it's out of control!
Any assistance diagnosing this would be great, if someone has had a similar experience, as I've got another trackday booked for Sat 29th, which is currently looking unlikely. Going to take it to a garage on Friday (away all week with work) but a few ideas for them to look at could help.
Homer suggested engine mounts when I mentioned it at Japfest?? All suspension bushes replaced with TRD kit and poly ARB bushes in the last year
cheers