Engine is missing when sitting at stop sign but runs good at highway speeds. why

Basic testing by a *competent* mechanic should be efficient for this diagnosis!

1st,pushrod is 100% correct on his answer as always because he KNOWS a thing or 2> because he's seen a thing or 2! You are probably frustrated with your truck and want it fixed NOW! If you have the 5.4L engine,DO NOT even think about replacing the spark plugs(not suggested) until you watch some videos on this(if needed,highly suggest having a pro do it),cause it could turn out very bad for your wallet! the Dealer here gets $500.00 just to replace 8 Motorcraft plugs on the 5.4L engine! Some call them *The Crazy Plugs*! Google part number SP507 for a picture and you will see. These plugs can/will BREAK OFF in the head,and it ain't good when that happens.there are some simple test that you or a person that knows these trucks could check, or if you start guessing at it,(throwing parts on it)then you could very easily have $1000.00 or more in it and the problem is still there! good luck... Part 1 -How to Test the Ford 4.6L, 5.4L Coil-on-Plug Ignition Coils easyautodiagnostics.com › Ford › 4.6L, 5.4L