I just got a 2006 focus zx4 with a 2.0. from what ive learned it should be a duratec? the car has 82000 miles on it and ran perfectly when i got it on monday jan 12, so good i kept thinking i was in a new car. i am very impressed with this ride. so my problem is i slowly sucked a 5th pint of seafoam into the break boaster line with the car idleing and warm, i then shut it off for about five minutes and then took the car for a ride around the block to burn out the carbon. the car never smoked until i got on it and the for a second it smoked so bad all at once i couldnt see behind me. after that it has a hesitation when you get around 3500 rpm. if you r accellerating it pulls smothly untill it gets to about 3500 rpm and kind of loses power for a brief second and then pulls on. i did this first then went home and put in new bosch iridium 4 tip plugs, i can tell a difference in the power and response of the car but it still has the hesitation. i did all this saturday and sunday morning the throttle flap or butterfly that lets the air thriugh was stuck shut so i had to take it off and clean it. i have used seafoam on my 5.4 60000 mi and 4.6 125000 mi and havent had any problems can you help?