I just bought a Ford Focus Black Edition( 1.6 Zetec Engine), and somtime's when idleing it seem's to choke it self slightly and the pick up again, it also does this when you leave your foot on the clutch for instance when you stop at traffic lights any idea's.

P.S. This is my first car so I don't know ever so much about certain stuff.

Mine does the same, Been told its the speed sensor, Costs about £30 from ford and can be replaced in around an hour....

Have you done your's and if so could you give me some tips on where about's it is and stuff.

yeaa defo the speed sensor, its somewhere around the gearbox

the speed sensor is on the back of the gear box just above the offside drive shaft oil seal.at the back of the engine,on the bulk head just to the right of the center there is a small plug with a wire going down to it. but it sounds more like an air flow sensor problem,check the breather pipes on the back of the engine for splits or collapsed pipes, also check the brake servo pipe for splits, you can normally hear a hissing sound if ones gone.

When I pump the brake(I did this as the brake felt abit spongy) it revs and then the revs kind of slow down the interior light also flashes when pumping the brake. It feels kind of rough at idle( feel vibrations through the car.