I have recently replaced my plugs on my 06 5.4L withh 100K miles. Truck runs much stronger now, but when the truck is in drive/reverse and not moving it still idles rough at times. I took off the throttle body today and cleaned it and the MAF but still happens. Any suggestions.

Thanks.
Nat

 

Check the air filter tray for missing foam. You have to have a good seal around it. When was the last time you changed your air filter or ran a can a sea foam through the gas tank?

 

Did you change them yourself? I ran into that whole crap spark plugs for 2004 to 2008 models. Mechanic changed them, told me to drive around the block to see if it idles rough. It did, then he thought to tell me that he had indeed broken off one of the plugs.

 

I will check for the foam seal, dont think its there. Sea foam is next. Had the shop put in motorcraft plugs, all but two of the originals came out in one piece.