I am seeing a lot of issues with Chev Cavalier and and the timing chain, so maybe not what I am thinking, but the issue I have is, after 1700. there was smoking from under hood - the pcv valve broken

off and the repair shop guy first started out with "well that was broken before we fixed
it" WHAT? then l said, "well that isn't important and won't make any difference." I don't
think they just throw pieces into a car for no reason. I see that a pvc valve will also
keep a car from starting if not connected, so that may have been the issue all along,
but even if not, what are some of the things that Could happen without the valve
attached? My son has super glued the thing back into place and we are hoping that will
hold as my finances are now depleted. Obviously not taking back to the same shop,
so just a heads up for the next shop I take to? Don't want to be taken advantage of but
need my car to run. Thank you.