2005 Renault clio vavavoom jerking, speedo not working, powersteering dies.

Hi, I am new to this forum and this is my first time posting something. I have a renault clio vavavoom 2005. A few months back my car started jerking when i am driving but when it idles and you rev it revs fine. The speedo does not work and sometimes it is as if the power steering dies when i drive slowly. The car also has central locking but it does not lock it self as it should when i start driving. I took my car to a renault garage and they said that the diagnostic did not show any faults but they wanted to change the ECU and fuel injection computer but it was to expensive. After some time googling my brother and I came to a conclusion that the speed sensor may cause all this problems. So we took the sensor (which we thought may be the correct sensor, On the gearbox , has a metal cap) we cleaned it and put it back but it made no difference.



I would appreciate it if someone could give me some advice or help me with this problem.



ps: the problem gets better when I drive for a long while. :crazy: