i hava 2004 fx4 with the 5.4 it has this shake wen its in park its nthn dramatic but its obviously not suppose to do tht. it dosent do tht wen im drivn down the road just wen im at a stop... wat coud b wrong

 

it was actin up again aftr work and the check engine light came on so i took it to my local repair shop n he hooked it up 2 the decoder thing and it turns out i have a coil in my 6 cylinder out n gas was just dumpn straight down the cylinder... he said happens all the time and i would end up replaceing all of thm b4 the pickup woud die. so hes orderin me one and will call me soon as it gets in n he can replace it.