I have a 2003 laguna 2.2 dci and since i broke down last october i,ve had a starting problem plz plz help?

I,VE HAD 2 INJECTORS CHANGED, AND THE CRANK SHAFT SENSOR, WE FIRST THOUGHT IT WAS A FUEL PROBLEM BUT NOW WE,RE NOT SURE, COS THE GUY THAT CHANGED THEM, FOUND THAT IF HE OPENED THE VALVE THAT SHUTS THE ENGINE DOWN QUITELY VIA A SCREW DRIVER DOWN IN BETWEEN THE INLET MANIFOLD RUBBER COLAR, (JUBILEE CLIP LOOSENED) THE CAR WOULD START EVERY TIME, BUT I CAN,T LEAVE IT LIKE THAT, THE FUEL FILTER HAS BEEN CHANGED, TWICE, THE CAR HAS NO OBVIUS PATTEREN TO WHEN IT STARTS OR NOT, BUT IT DOES SEEM TO START BETTER AFTER THE FIRST TIME, UNLESS LEFT FOR ANY MORE THAN 15 MINITE,S, I,VE BEEN TO THE RENAULT DEALER BUT THEY WANT TO CHARGE ME �85 TO PUT A TESTER ON IT AND IF IT STARTS THEN IT AIN,T GOING TO TELL ME ANYTHING AND TO CHANGE THE FUEL SYSTEM ITS �3000 AGH !! IF ANYONE CAN HELP PLEASE RING 07957 132414 ASK 4 PAUL THANKS soz only now seen the CAPS thing