Focus Keeps Jerking

[luv2vexx]

I have a Ford Focus 1.6 Ghia, 2005. I had water in the spark plug wells, after finding out, I had the HT leads changed, the core plugs changed, the wind screen washer jets changed (Orignal for part, without leak fault) and had a service done on the car, the car still jerks while driving, don't know what else to, some help will be much appreciated.

[mintalkin]

it could be a coil pack playing up.