When I run my truck wot it throws a code on the dash but nothing when I plug my efi live in. What could it be and why does it throw the Light but efi live can't read it.

do you notice any decrease in performance? if not then i wouldn't worry about it. if there is any symptoms then let us know about it...like i've said before and i i'll say it again "if it ain't broke, don't fix it" let us know.

no performance difference just would be nice to know what was triggering it. Check engine lights are just a common occurance with everything it seems haha especially when they arent any where close to stock.