175 k miles, 760 gle 1989

car stalled on freeway, would not start.
removed valve cover, chain was tight. turned motor over
had "mechanic" look at it he says chain is loose,,
"floppy". motor turned approx 15 seconds only.
questions: is this possible,, being loose?
if loose, has the chain moved a cog on the gears
and is the timing off now?? how to check??
would replacing tensioners only solve this problem
or am i just toast and need a new chain?
am looking for the cheapest way out of course.
also what is approx cost to have this replaced if needed,,
not big in the wallet right now

thank you,,

doug