I bought my 06 off road in April 2006. I worked out of town for until 2008 so it didn't get much mileage on it. I now have 43500 since I am now retired and drive it a lot more. Noticed that the fuel economy, If you can call it that in an Xterra, has gone down lately. I am going to run some injector cleaner through it this week and see if that helps.