Done mine this morning
1.8 focus mk1.
Took off air filter and intake hose. Felt around for this...thing... found it in the awkward place under the intake manifold on the rear side of the engine, to the passenger side of the throttle body.
2 bolts, 1 on top 1 on bottom, 8mm socket needed. I loosened the top bolt and unscrewed it by hand. Loosened the bottom bolt by going in from underneath and loosening it, unscrewed it by hand from the top. Then pull off the cable.
Took it out to clean it, had no carb cleaner, soaked it in petrol and red ex.
Reset the ECU by detatching the neg battery lead for about 30 mins. Reattached everything in reverse order.
My symptoms were rough idling to the point that the engine would stall after decreasing rapidly in revs from mid/high to idle. The engine would be fine if I slowly decreased the revs to about 1000 then i could idle/go neutral. Tested it by warming up the engine, revved it hard and jumped off. Now it quickly goes to idle and stops still at about 750 rpm. Fixed.
If you do the same and it doesn't work, check EGR system for leaks or faulty EGR valve (that flying saucer lookalike thing- mine is to the drivers side of the throttle body, but it has been known to be pretty much anywhere on these foci.)