my car starts to jeck when on a full running temperature

[ese]

I do not know if anyone can be of help to me. I do have a kind of problem with my lancia 1.6ie 1990 model. When the engine is warm or hot (normal) the car starts to "jeck" and not getting full power. Do you have any suggestions on what could be wrong? The car runs very fine when not hot. This is a new problem I just noticed after I just changed the water pump. thermo switch and thermostart. The air filter seems clean and the plugs very ok, the distributor cap and distributor looks clean too.... What could the problem be? Please help me if you know something.
Thank you
Ese

[Ethan]

Sounds very much like a problem i was having with my hf turbo! Is you car also getting crap mpg?

Mine was and the car would seem to almost have a power loss and jerk when changing gear and the car was hot!

I put this down to the ECU what with the fuel and everything, just so happened that i had another ECU so replaced it and the problem seems to have gone....... Please note i replaced the unit last night so time will tell. Hope i've helped.