Yes. clutch kit was replaced (clutch, pressure plates and release bearing). Didn't cure the problem. I think more and more it is something related to engine. I am 99% sure it is not air. So I have left fuel and spark. I have changed the spark plugs but not wires. I guess wires give you trouble in high speeds, not in low speeds. Now I have left fuel. will check and change the fuel filter this week end.
Have anyone come across this kind of problem?