I have a 2004 f-150 5.4L. When starting it first thing in the morning the truck shakes and rattles like it is going to blow up. Then once it warms up and when driving it will feel like it is goiong to die and we have to two foot it to keep it running. Had it put on the computer and the only code was for the crankshaft positioning sensor changed both banks and no difference. Just changed the air filter a week ago and today the filter is completely black. I am thinking of changing the spark plugs. The maf. Does anyone have any more suggestions on what else i can check. Thank you in advance