2006 Ford focus engine and electrics problem?

My focus has a problem that it jerks on acceleration and if you rev it while standing still slowly it seems to miss about 500 revs till it works ie if it ticks at 800 revs you press the pedal slow and it goes to rev and jerks to about1300 difficult for pulling away as you have to double dip it cause it goes to stall, also if you hold it round roundabouts slow and even, it jerks its not as if it does it when accelerating in fact it is better being driven hard!! a twist is when my rear window wiper goes haywire and stops where it wants and my radios memory wont hold the car runs fine and runs on, on slowing down instead of jerking, any ideas im baffled ive driven other fords and they dont feel like this one!!!!!