1999 Ford F150 Premium Sound?

Hello everyone, I am currently not getting decent sound at best out of my door speakers. I have bought my 1999 f150 xlt with an upgraded h/u door speakers etc, I have since replaced all four dour speakers as well as changed head units to my preferred brand. For the life of me I cannot figure out why the door speakers sound so horrible. I do have an aftermarket amp and subwoofer but as of right now I am in between changing a few things up on my enclosure, with that being said I cannot even stand to drive without my sub bc my speakers in my doors sound like crap, they sound hollow weak and as if they have no bass. Do I have a factory amp somewhere I am missing? I did have a 6 cd changer in my center console (Factory). There is also an extra unused harness behind my H/U. I have yet to locate the amp as I have had little time. I Have also noticed the wires into my door speakers color codes are no where to be matched up to any wires to the head unit, leading me to believe that somewhere these wires are changed ...I do not want to have to try to re wire my door speakers..any help would be greatly appreciated..thanks in advanceBig Rich