what would cause my truck to shift from 1st to second fine but won't shiftto3rd

What is your question?

my truck sat for a little while i recently put it on the road it ran an drove fine i washed it the other day n since then the truck runs great shifts from first second smooth but won't shift into third and if it does its like its in neutral and check engine lights now on any ideas what it is an can a camshaft position soelinod cause this issue plzzzz help