you may need to swap dist. box. coil,with known good parts 1 at a time from a friend or something
or bring it to a preformance ignition place to have it checked
if it checks out good you'll need to look in other places
don't get stuck in one problem. valve float may sound the same.
pull on all the wires tite'en up lose stuff.
try shiffing at 6800 or 6500 to see if it runs through