Keygrip
The fuel-flow meters on most pipers are not very reliable. In fact most people will prefer to calculate time x consumption rather than rely on the meter.
A JPI760 is an instrument from jpi.com which is able to analyze engine data thanks to probes (GAMI) on all cylinders. As a bonus you can also have it fitted with a very accurate fuel-flow meter, which ,assuming you have registered the correct fuel volume at the start of your flight allows you to keep very accurate track of your fuel remaining.
However the main benefit of the JPI is that it measures temperatures on all cylinders as opposed to one cylinder per engine which the default temp meter does. The probe for this one is generally fitted to the cylinder which on most engines is the hottest, however there can be variations and by using the JPI you can always see which cylinder runs the hottest.