While accelerating from a stop with the ecoboost system, the car will almost stall, then speed up with out your foot on the pedal. It blows black smoke and then it will be fine. This has happened on and off for the past several months, the car had an extended warranty in which this showed up. While this was going on I have had to replace the power transfer unit because it locked up, then the car would only work in front wheel drive, have had nothing but trouble since the car radiator fan system burned up and they replaced. They have re-flashed modules after they could not figure out what was happening, however it still does it. I am worried as the car has speed up to 2000 RPM while driving and stayed there with out the gas pedal being pressed.

- Osceola, IN, USA

Upon acceleration, usually from a complete stop such as accelerating from a stop sign or on a green light, it feels as though the gears do no catch & the car jerks and the RPM's raise but the car stops accelerating. Will also have a "stuttering" or "jerking" while at a complete stop with break pedal being pressed down. I have taken this issue to the dealership as it is still under extended warranty and have been told that everything checked out normal & the mechanic at the dealership was unable to get the vehicle to have such described malfunctions because it is doesn't happen every single time the car is driven. The jerking while driving actually occurs on a daily basis but is sporadic & can jerk you forward due to the sudden loss of acceleration capability, startling and painful because the seatbelt mechanism has engaged in the past.

- Chico, CA, USA