VG33e MPG problems
I have a 97 pathfinder SE with an auto transmission. I was getting 18mpg highway and 15mpg city. Driving cross country 10 months ago, I fueled up and the pathfinder has been getting around 13mpg highway and 11mpg city every since (track mileage every fuel up by dividing miles traveled by gallons used). I have done the following with no luck. Changed spark plugs, fuel filter, thermostat, temp sensors, water pump and timing belt, bled cooling system, oxygen sensors, and checked exhaust for a clogged cat. No CEL or performance issues.
On a side note the mpg did increase to 18mpg for one 300 mile trip in which the outside temperature was around 0 degrees F. Went right back to 13mpg following warmer temperatures the next day.