Citroen C5 car judders quite badly when cold, after a mile or so it is fine

Possibly engine temp coolant sensor ?

Sorry to sound a bit dim. Not sure if I explained myself properly. if I jumped into my car when its cold and tried to drive off, I have very little power and the car judders quite badly. After I have been around the block and the engine is warmed up the car drives normally and the judders dissappear. A friend suggested it could be the coil pack (but he's no mechanic and I am certainly not). i have a long drive to do at the weekend and I am obviously concerned if I will make it. the engine burns oil and I may have put too much in, when topping it up. Could this be a factor. many thanks for your help.

Sorry to sound a bit dim. Not sure if I explained myself properly. if I jumped into my car when its cold and tried to drive off, I have very little power and the car judders quite badly. After I have been around the block and the engine is warmed up the car drives normally and the judders dissappear. A friend suggested it could be the coil pack (but he's no mechanic and I am certainly not). i have a long drive to do at the weekend and I am obviously concerned if I will make it. the engine burns oil and I may have put too much in, when topping it up. Could this be a factor. many thanks for your help

Depends on how much oil was put in . If it was only a small amount i.e 1/2 pt wont make any difference .The engine temp coolant sensor lets the ecu know how much fuel is needed , a richer mixture when cold , like the choke on old cars .If its burning oil , certainly doesn't help starting .