Is the fuel flowmeter in the newer Cessna 172s (and others?) a true flow meter
(as in a small turbine meter generating pulses, etc.), or is it a pressure
gauge or pressure transmitter measuring the fuel pressure in (whatever)?

I got the you-know-what scared out of me while in flight and this *&^#@ thing
read ZERO, though everything else (RPM, EGT) was normal. It was OK before
take-off. It finally came off zero, but read low.

Hmmm?