Sounds like a vaccum leak
Clean the carbeurator and lube the throttle cable.
could be a vacuum leak, or throttle positioning sensor
have you ever changed the fuel filter ?
I don't think your asking the Q right it must be the engine doing it, maybe egr
I would check the ignition timing and set it to the desired specifications. Next I would clean the throttle plate.
MINE WAS DOING THE SAME THING AND IT WAS THE EGR VALVE!! THAT FIXED IT AND IT'S RUNNING GREAT!!:)GOOD LUCK
not 100% sure, but check your fuel pump
It's lean. Check for vacuum leaks, and make sure the fuel supply is functioning properly.
the reason the throttle would be sticking on your focus is that it (the actual unit) could be dirty. or the throttle cable could have dirt in its casing. what you need too do is remove the throttle cable and spray engine degreaser in the casing and hang it up too let the dirt and grime drip from it. be sure to use wd-40 to relubricate the cable. now as of the throttle body do the same thing. but use a non abrasive cloth and wipe the unit clean. make sure there is no dirt in any small cracks or crevises.
I can tell you with relative certainty that the condition and/or operation of the spark plugs should have nothing to do with a sticking throttle. Your best bet would be to check your throttle body for buildup or debris. Also you might check the throttle return spring on the side of the throttle body.
No
because itt needs to be work on