only getting 15 mpg
 

Hey guys I have a 98 z and my gas mileage is not what it should be. I use premium but am barely getting 200 miles to a tank :eek: . It has 106 k and runs great. What can I do to improve my gas mileage? I am starting nursing school and I commute so it would be a huge help to get better mileage :) thanks!

Re: only getting 15 mpg
 

Tune up???

Re: only getting 15 mpg
 

Could be a "false lean" condition caused by misfires or exhaust leaks before the O2 sensors. That causes the PCM to add fuel the engine doesn't need, runs rich, poor fuel mileage. Or you coolant temp sensor may be reading lower than actual temperature. When the PCM thinks the engine is cold, it richens the fuel mixture, just like the choke would do on a carbed engine.

In the winter, they up the oxygenates in gasoline, and fuel mileage drops as a result. You are also running the engine cold for a longer period of time, and that's going to reduce fuel mileage. You don't indicate your location, but if your from up north, mileage drops in the winter. An increased mix of city driving vs. freeway driving will produce results under 20 MPG.

You might want to actually measure the fuel you add to fill it, and the mileage driven on that tank, so you can get the actual calculated MPG. "Miles per tank" is nebulous at best. best.