My 4.6l 3v 6spd has a tendancy to stumble and chatter in town around 30-40 kph. Dealer told me it needs a spark plug change. Pressing the tow/haul button temporarily helps but it can do it in tow-mode also. Truck is not a work truck but driven like a car-equally town/country. Does 2010 4.6 3v have the same sparkplug removal problems as earlier models?