If this vehicle has high mileage I would start with the plug\wires and oxygen sensors. These would all affect fuel mileage on higher mileage vehicles. Hope this helps you.
A 6 cylinder Toyota Camry LE has a gas mileage of 21 miles per gallon. The highway mileage is 31 miles per gallon.
The Toyota Camry gets good gas mileage and is very fuel-efficient. The Camry averages about 28 miles per gallon. The hybrid version is even more fuel-efficient, averaging 41 miles per gallon.
The Toyota Camry achieves a gas mileage of 33 mpg in the city and 34 mpg on the highway.
500,000 miles
The EPA mileage estimate for the 2014 Toyota Camry is 25 mpg in the city, 35 mpg on the highway.
The EPA mileage estimate for the 2010 Toyota Camry is 22 mpg in the city, 33 mpg on the highway.
The EPA mileage estimate for the 2003 Toyota Camry is 21 mpg in the city, 30 mpg on the highway.
The EPA mileage estimate for the 2008 Toyota Camry is 21 mpg in the city, 31 mpg on the highway.
The EPA mileage estimate for the 2009 Toyota Camry is 21 mpg in the city, 31 mpg on the highway.
The EPA mileage estimate for the 2001 Toyota Camry is 20 mpg in the city, 29 mpg on the highway.
The EPA mileage estimate for the 2013 Toyota Camry is 25 mpg in the city, 35 mpg on the highway.
The EPA mileage estimate for the 2002 Toyota Camry is 21 mpg in the city, 30 mpg on the highway.