i have 2000 rx impreza, the problem i am having is the car starts to shudder at about 100km/hr. after i have stopped the car and take off again it is fine for about 150km. the car now has a new gearbox and ujoint. same problem as before. any ideas?

i have 2000 rx impreza, the problem i am having is the car starts to shudder at about 100km/hr. after i have stopped the car and take off again it is fine for about 150km. the car now has a new gearbox and ujoint. same problem as before. any ideas?

RX????? What country are you in??? What about the front wheel bearings? Or maybe (but I doubt it) the wheels are out of balance.

Sounds like jolly ol' England or the land of No Worries. It could be a wheel wobble, but it goes away after the engine has cooled down, so it seems to me it is engine related. It could be a air/fuel mixture problem, having to do with the thermostat. Check into that area. Normand, do you have a troubleshooting / repair manual for your car? You might be able to find one at a local auto parts shop. Definitely a good investment, and if you can use a wrench, it will save you hundreds by fixing it yourself! Good luck!