Hi Wy.

[wywindsor]

Joined to figure out mpg after dealer change the fuel sender assenbly on my 2008. I dropped 5 plus mpg. I tried to post on discussions but can't . Why



Ray

[xtopherfishing]

Hi Ray, glad you are joining our discussion group here on this forum. Can you give us some more details about your truck? 4 cylinder, 6 cylinder, automatic, manual tranny, odometer mileages, etc. You can even add those in your signature line so they will print with each posting you do here (it saves a lot of questions having to be asked each time you post). I don't know the reason for why the forum system would not let you post under General Discussions....maybe one of the Administrators can answer that. Welcome, and we hope to hear more from you.

chris

[wywindsor]

It's a 2008 with a v6 4.0 4x4 nismo. I was getting 18 to 22 on the highway and 14 to 16 in town. I live in casper Wy. at 5280'. We have a winter blend fuel here. I work at refinery and know we ollse a little bit of mpg in the winter but not 5 all around. I took the truck in for a test on the radiator and tranny leak ck. They put the new fuel sending unit in it on a recall issue. Since then my mileage has dropped 5 + mpg. This is 5 tank fuel ups. The dealer said we was not the only one's to complain about this but blamed the fuel.


Is there a chance the fuel return line got pinched or the fuel pressure reg is in the tank like a gm product and it's wrong.




Ray

[invasion08]

I am blaming the fuel too. My mileage this winter is worse than last year.

[wywindsor]

I have a 2001 mustang and a 1990 mustang. They dropped 1 to 2 mpg with normal warm ups so fuel it is not. I have never had this king of mpg decrease in the nissan. I work at the locasl refinery that supplies gas to the area. I have ck with the lab and we have a spec to meet. The spec has not changed.

I'm getting 13.5 on the last fill up. This was 240 miles at 75mph. I got 10 mpg the last in town fill up.

[xtopherfishing]

I know that on my 4cylinder here in Iowa (a cold winter state) my idle rpms go up during colder weather and the longer the weather stays cold I will keep getting reduced mpg's at fuel up time. My in town mileages drop from about 22 summertime to nearer 20 winter. My hwy mileages can drop from 25 summer to 23 winter. Some say its the winter blend gas but I think it has more to do with longer high idle times due to colder air temps. I had one two week period a couple of years ago when I had one intown tankful go to 17mpg....but that two weeks stayed below zero F almost the entire time. At 5,000 feet elevation I am not sure how that plays with your tuning of air and gas mixture. Those settings I think are done at the factory, did the dealership or anyone try to adjust the timing of the engine? Did anyone check the oxygen sensor? I would assume the check engine light would come on if the oxygen sensor had failed.