hi, just recently bought a fiesta 1.6 xr2i and its a little bit jerky at low speeds and when u come off the throttle and then go back on it. also feels a little bit lumpy on idle. car is totally standard, genuine 42000mls full ford service history. cheers.

 

1st get the emissions checked,suspect throttle potentiometer

 

check the idle control valve and its plug, check the vac pipes, also check the throttle position sensor.
to be honest though, sound like it needs a set up, when was the plugs and leads last changed? fuel filler isnt due till 60000miles but could prob do with a new one if it never been changed.
whats the breathers like? free flowing or resrtictive?

my RS done it a bit, once it was set up it was sweet as a nut.
i had to have my fuel pressure upped andmy Co2 adjusted as i fitted a chip etc but you may just need the Co2 tweeked

PM me some more details of what you have checked etc.