I have a renault laguna sports car V REG. since the cold weather it judders badly and then comes to a halt. after a few mins its fine for a while then judders again. i have has 2 sensors, sparkplugs and leads fitted at the garage they said that they cant see anything wrong with the car. it is to dangerous to drive on the motorway at this time. has anyone any ideas what could be the problem? could it be the fuel pump?

george sims, November 2010

Hi George.
Is the car diesel? It sounds just like water in the diesel fuel. If it is, there is normally a drain plug which will be shown in the car handbook that allows you to drain water out of the fuel line.
If it's petrol, there are obviously lots of things it could be, but you could try the common, cheapest remdies first:
1) Remove the sparkplugs and throughly clean the spring wahsers and the engine block where the plugs are seated.
2) Remove the distributor cap (at the other end of the HT Leads) and thoroughly clean inside, removing any 'crust' from the electrodes and also clean the rotor arm metal parts.
Neither of these will do any harm and it might just solve your problem.
I hope this helps.

Barry, November 2010