"Green" xterra
 

Last year I got a 2000 Nissan Xterra v6 4x4 5 speed. The funny thing about the xterra is if you search top ten vehicles with the worst mileage the xterra will be on that list competing for first place with v-12's and other high performance engines. My starting base mileage was 13 mpg on the highway and 11 mpg in the city. Which is below the epa rated mpg due to some mechanical issues. But since then my mileage has increased quite significantly. Here are the list of some modifications I have done over the past year.

So first things first I did the necessary things to get the xterra rubbing right again and replaced some sensors that have a major affect on the fuel economy. First I replaced the old o2 sensors with some new ngk o2 sensors. Replaced the mass airflow sensor, did the ignition timing, switched out the mechanical fan with the electric fan, took off the a/c. All of this was pretty good to do but didn't make a huge difference in fuel economy. I was probably starting to get 14-15 mpg highway at the time.

After I done maintencance I started getting into some other mods that required a little more work. One of which was deleting the cats and putting in o2 fowlers to keep me from throwing codes. This was good and made the truck sound better but it didn't really free up any extra mpgs.

After that I had a road trip to Utah. It was a long drive and my fuel stops were quite frequent. And I was boasting a solid 13-14 mpg the whole trip (do to the higher speed limit and big hills) when I got down I noticed my engibe was running quite rough. I was having the same problem before and thought it was the ignition rotor cause they do tend to fail in the xterras and when I replaced the dizzy it made little difference. So when I was in Utah I thought that maybe I had a leaky egr valve. So I deleted the egr and the engine ran smoother and on the way back I started getting 16-17 mpg the whole trip which was a welcome change.

The next thing I did was change out the fuel filter and fuel pump timing belt and water pump just as some routine maintenance. no notable improvements. The one thing about this truck is that I've always had this underlying mistery problem. Poor throttle response between 1000-2500 rpm, extremely poor acceleration (we're talking 0-60 in 23 seconds) and random sputtering/hesitation. With the only code being low o2 voltage since I got the x. Still have not figured it out to this day but I think I'm getting closer.

The biggest improvements I have seen so far is when I did the exhaust and knock sensor back in April. I had a crack in my stock manifolds and I didn't want to replace them with some thing that is just going to crack again so I installed stainless steel headers. My build and intent on this build is to increase lingetevity of the engine, increase mpg, and gain back my lost power. And when I did the exhaust it made the biggest difference so far. I did the headers and a manga flow muffler. And with that I gained 2-3 mpg. I went from 15-16 mpg on the highway to a solid 18-18.5 mpg on the highway.

Next big game changer. I ran a couple of bottles of seafoam through the engine and also a quart of atf. This is really smokey especially the att but the main reason I did the atf was to clean the combustion chamber. It is proven that because of the detergents in atf it will clean you combustion chamber more effectively than sea foam. after doing this my mileage increased the most it ever has. Jumping from 18-18.5 to 22 mpgs solid. If someone can teach me how to upload photos from my iPhone I would explain to you why that made such a big difference.

Seriously not trying to be a butt, but why do people buy vehicles with absolutely horrible mpg, and then want help trying to squeeze better mileage out of it?

Because sometimes the car you get is the car you get. Given "this is my car," you do the best you can with it.

I should have bought my Honda sooner- 8 month in the Xterra aws hell.
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Better Mileage
 

It doesn't matter what we drive, it matters how we drive!:)