Three days ago my 2000 4.0 Ranger XLT Supercab started missing. It will miss and shake badly for 4-5 seconds and mostly clear up then repeat. Begins at startup, engine cold or warm. It has 245k miles that are mostly highway and factory build-no mods. There was a fuel fill up about three days back, otherwise nothing more to add. It has been great truck and I want to drive on into my retirement. I have a garage and am capable of the work but have no ideas other than blindly shotgunning parts. Help me please.