if its the engine that judder's the car you could have a throttle body full of crap? Do you have panel filter? could need cleaning and re-oiling
On a corrado this happened, the throttle body was filthy, also it was getting a lean code from the oxygen sensor, air filter was filthy also and plugs carbonned up ie overfuelling.
So I agree with above, id clean and check everything you can ignition etc.
then check fault codes if any.
I think also check vacuum pipes, air hoses, electrical connectors, battery terminals.
This is a common issue on google but without one exact answer, so its a case of eliminating im afraid.
btw I dont think we changed the temp sensor, might be worth disconnecting that while running, if its working the engine note should change.