I have read that the coil packs are bad to short on the 4.6 motor. could they only miss at certain RPM's? my truck runs fine at certain RPM's, but misses at most times

 

I just had a coil pack go bad on me. Seemed it only missed after the engine ran for a least a few minutes. My code reader told me what cylinder it was, replaced it and its like new again. I would just do that.

 

AutoZone can check coil packs for you if you don't have a DVM yourself

 

Do you have a CEL ? You should if it misses that much. Your CEL will blink then shut off. Even tho your CEL may not be illuminated, you still have a DTC stored. Get it scanned for free at Auto Zone, like torkum suggests.