I got 31MPG out of my mom's 2005 Nissan quest sl,i took it for a test drive right after i have changed all 6 spark plugs to NGK platinum(they are rated for 100k) i also changed it's transmission oil+ installed K&N Air Filter and i did ecu relearn+idle,i always use 91 octane free gasoiline on it.Before i was only getting around 25-27 avg on the freeway and 20mpg in the city.I find with this van that if i use the 10% ethanol gasoline on it,the city mpg would drop down to 12-15! with no ethanol i'm able to get the epa city rated mpg which is 18mpg and i can sometimes get up to 21 with some hyper milling.
