If you're only getting 25 mpg when hypermiling you probably need a tune up. Expect ~$100 in parts for a good engine tune up. I ordered all my parts from Rockauto.com for under $75. This included an Air filter, Fuel filter, Spark plugs, Wire set, Distributor cap, Rotor, and PCV valve.
I also changed the engine oil to Pennzoil platinum 5w30 synthetic. I drained and filled the rear diff with Amsoil 75w90 Synthetic GL5 and the transmission with Amsoil 80w90 GL4 Synthetic. The transmission definitely shifts a lot smoother with the amsoil fill. I don't have any grinds between shifts, which I had with the stock Nissan fill on cold mornings.
I consistently get 28-30 mpg. I drive about 70% highway 30% city. The single best thing I got for increasing my mileage was a ScanGauge II which is incredibly useful not only for monitoring mileage, but for scanning for codes, checking various engine vitals, and having a great trip meter function. I also just put an awesome horsepower program on it.
I also changed the engine oil to Pennzoil platinum 5w30 synthetic. I drained and filled the rear diff with Amsoil 75w90 Synthetic GL5 and the transmission with Amsoil 80w90 GL4 Synthetic. The transmission definitely shifts a lot smoother with the amsoil fill. I don't have any grinds between shifts, which I had with the stock Nissan fill on cold mornings.
I consistently get 28-30 mpg. I drive about 70% highway 30% city. The single best thing I got for increasing my mileage was a ScanGauge II which is incredibly useful not only for monitoring mileage, but for scanning for codes, checking various engine vitals, and having a great trip meter function. I also just put an awesome horsepower program on it.
