Hi everyone My Parents have a 2003 Focus ST170 and for a good few months now on and off when the revs reach about 4-5k it judders like mad.

They had the RAC out to it a while back and he took one of the pipes off i presume the Cannister Purge Valve Can anyone help me out with this problem as it is really annoying thanks in advance with all replies..

 

I would try looking at the fuel pump, but change the fuel filter first. Check its got the right plugs too, ST170's have different plugs to the 2.0L zetec and 9 times out of 10 you get Zetec ones fitted. Coil pack also has a habit of playing up. At them high revs the VVT and Dual stage manifold runners switch over, could be the VVT controller, but if there is no fault code its very difficult.

 

thanks for the reply ill take a look and reply to let you know the outcome

 

had the same problem found it to be the fuel pump after a few months of fault finding, very common, also check runner control, but would bet it's the fuel pump

 

thanks gray i did think about the fuel pump but wasnt entirley sure