CEL and fouled plugs

[acdii]

Since the Cmax and fusion share the same tech, thought I would post here too. I just got my car back, with no repair done other than replace the plugs. At 4500 miles while taking the family out to dinner and pulling onto a rural highway(55MPH) the car stumbled at 45 MPH CEL started flashing and car shuddered a bit then smoothed out, a few miles down, made a turn and accelerated again and CEL blinked again. Got to dinner, ate, and trip hime, uneventful.

 

Next day, 12-31 drove to work, no CEL, time to go hime, pull out onto city street 35 MPH, then a somewhat steep incline, get to top to 45 MPH, hit the gas and solid CEL. Stayed on all the way home. Wednesday got in the carr CEL still on, drive to dealer adn pull out onto the same road as before, and even with the CEL on it started blinking, and stumbled again at 45.

 

Car was in the shop all day, untouched since it was unscheduled, then next day they pulled it in and found all 4 plugs were fouled, but no other codes beyond the misfire. They test drove it over night on a 100 mile trip and came back, no codes, and the computer reported good MPG. Car was returned to me to drive and see if the plugs foul again, and it is still getting poor MPG, only getting about 36 when it should be at least 40.

 

You would think that on the second report of this car that it still doesnt get good MPG after 4500 miles, with documented proof of actual fills vs miles driven, and 4 carbon fouled plugs, Ford would pay some interest in it as hmm, poor FE and fouling, maybe a sensor is bad.

[gultim]

I experienced the exact same spark plug issue.  I have worked with engines for more than 35 years and with a correct fuel/air ratio the engine should never foul a plug.  Carbon fouling indicates the lack of oxygen (or too much fuel) to fully combust all the fuel.  The fuel/air ratio in our cars are too rich resulting in fouled plugs, lower than rated MPGs, higher than normal fuel consumption, and accelorated engine wear. 

 

I have a second issue...upon decending a 10% grade mile long hill in hill decent mode and with a full battery, my C-Max is randomly/intermittently surging and missing as it warms up till it hits about 135F and the RPM drops to 1150 ish, then the surging and missing dissapear.  At first the surging made me think I was experiencing a mini Prius stuck gas pedal issue as the surge made me almost tap a car in front of me...this happed twice, now I apply the brakes harder when stopped.

 

I'm hoping Ford and my dealer can resolve these issues as I love the rest of the car and I would prefer not going through the lemon law/arbitration/what-ever-it-takes hassle. 

[plus 3 golfer]

Do you guys know the trouble codes for the CELs? A good dealer should list them on the service order. Is it misfire codes? I wonder if the car is not going into closed loop operation or staying in open loop too long.