Amazing...all those answers by 172 owners and no one of them went to the net to
find the "truth".

If you go to Google and fill in "Airworthiness Directive for 172 fuel system",
you will get a string of answers and some really foolish conclusions (like this
string) that are worth reading.

One states...my plane has the placard to not fly on both above 5,000 feet, but
I did and the engine quit at 8500. Sigh (mine).

If you know how to get to rec.aviation.owning of the Usenet, the string is
there.

Note that the problem is model/version specific.

Neal