mpg DROPPED

[newpath]

I've read the stuff that people have suggested to get better mpg, but I'm a little curious if that would do any good since I just had a fuel system/injector service done this past spring. I have 62k miles on it, and I run premium in it all the time. I was getting just under 18mpg, and each fill up after I got that reading has dropped. I'm now down to just above 13mpg. I did a little more city driving this last tank but not a ton. And the city driving I do is never more that 5 minutes worth...literally. I was going to try sea foam but again, I don't want to waste the money if it won't do any good. Any thoughts or suggestions?
P.s. it's a 2002 LE 4wd and I rarely use the 4wd (since we've gotten hardly any snow this year...I'm in Michigan) or even the auto function. It's always in regular 2wd.

[zymol75]

Everyone needs to remember that Ethanol is killing all our mileages. It consumes more energy to use than it returns. It is just the way of our nations energy issues. I keep an eye on my mileage but honestly if It mattered that much I'd drive a Civic or a CBR1000. I fill it when it's empty and drive till I fill it again. I have enough stress/crap to worry about without freaking out over 4 mpg. (not insinuating that you are freaking out) life is too overloaded as it is... enjoy the ride.

[newpath]

I agree with you, if it was that much of an issue, I'd be driving something that got better mileage. I'm really just wondering if something is "wrong" , or "broken" that has caused the mpg to tank. I don't really want to pay the $70 for them to tell me nothing's wrong.

[05Pathfinder]

It could be lots of things and the weather is definately a factor.

Off the top of my head take a look at your spark plugs, O2 Sensors, fuel filter plug wires (if you have them, not sure)... Also try a different gas station for a little while to check the fuel. Lots more you can check but I would start there.

[bluepathy97]

Running premium gas can also drop your mileage. The higher the octane rating the harder it is to burn. I use regular old 87 and I get around 19 mpg around town.

[Litey]

yeah cars get less mileage in winter , cause the air is less dense and harder to push through . Also like the above post the ethanol and
less octane in winter gas . I just had the same thing I went from 18 avg to
like 15/16 ... just changed my air filter , had 20k on it a bit too much ,
mileage got better but still lower than summer .
Mine is 04 LE .

[Datsun_Dime]

Running premium gas can also drop your mileage. The higher the octane rating the harder it is to burn. I use regular old 87 and I get around 19 mpg around town.

That only applies if your vehicle requires 87... If it calls for 91 thats where your going to get the best performance/millage... The VQ35's have a 10.5:1 - 11.0:1 CR range that requires 91 for optimal performance/economy. 87 wont hurt it but will decrease performance and economy (engine knock sensor will detect pre-detonation and retard the timing automatially)

[Datsun_Dime]

I've read the stuff that people have suggested to get better mpg, but I'm a little curious if that would do any good since I just had a fuel system/injector service done this past spring. I have 62k miles on it, and I run premium in it all the time. I was getting just under 18mpg, and each fill up after I got that reading has dropped. I'm now down to just above 13mpg. I did a little more city driving this last tank but not a ton. And the city driving I do is never more that 5 minutes worth...literally. I was going to try sea foam but again, I don't want to waste the money if it won't do any good. Any thoughts or suggestions?
P.s. it's a 2002 LE 4wd and I rarely use the 4wd (since we've gotten hardly any snow this year...I'm in Michigan) or even the auto function. It's always in regular 2wd.

How may miles to a tank are you getting..? If your losing a total of 30miles or so to a tank, the cold weather is probably to blame... I get about 50KM less to a tank in the winter.