I wouldn't bother trying to get economy readings on 4 and 5 gallon runs.

As was stated earlier, the % error will kill you on such small fills.

Wait until you can pump at least 15 gallons to minimize the effect of normal variations in pumping etc.


Tim

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2009 VW TDI Jetta Sportwagon 172k miles (rear-ended harder than Elton John on 8/4/13. Total loss)

1991 Volvo 240 142k miles (T-boned by a stop sign runner. Total loss)