I knew your name looked familiar but i couldn't put my finger on it ^_^.

 

Toyota 3VZ-E V6: Power of a 4 cylinder, fuel economy of a V8!

After you install the new O2 sensor, go get a tune-up. At 205,000 miles, it probably needs one. You also stated you had 31" tires, but you never said what kind. If they were like mud or all terrain tires, then your mileage will suffer a bit due to rolling resistance. Cold air intakes don't usually work unless you have a free flowing exhaust to match it. In your case, with the turbo muffler and lack of cat, there is a possibility that you could see a mileage improvement. A set of headers would help to increase exhaust flow, and in our case, decrease the likelihood of head gasket problems. However, few companies make them and they are very expensive.

To add to Kiroshu's list in post #12, replace your fuel filter. It's probably not the #1 culprit, but it wouldn't be anything but helpful.

I have the V6 and with stock gears and 32" all terrain tires, I average 16-19 mpg (after accounting for tire size). Last summer I went through a tank of gas and calculated 20.5 mpg, my best mpg ever. However, this was the time before I accounted for the larger tires. If I accounted for tire size, I really had around 21.5 - 22 mpg. So it is possible to get some fairly decent mpg out of these engines.

 

Mine are 31" mud terrains with the majority of the tread worn but still enough to be loud and bumpy

 

The guy I bought it from used it primarily for boondockin' so I don't know how good any of the components are.

 

It also can depend on the brand and model of mud terrain tire. Some get better economy than others.

 

They are Deffinity Dakota M/T if that tells you anything.

 

that tells me why they are bumpy. I had a set of those tires a while back on an 86 4runner and broke belts in all 4 tires within 3 months of purchase. How does the tread wear look? I'm not saying it is your problem but it happened to me.

It didn't do anything to my mpgs but it was very very annoying.

That said, I get great gas mileage when I have my girlfriend drive us in her Cavalier lol. My 4Runner 3.slo, maybe about 14mpg on average. MUCH MUCH better with long long light throttle flat land highway excursions. Steep hills gaining in altitude from 3500-10,000 feet or tons of stoplights, brutal. Its part of the game. I still love my truck

 

Have your timing set Properly.

But this can Only be done correctly, after your Trottle Position Censor TPS.....is set properly. This must be done!

Your new Oxygen Censor will work with the new settings and you should see an improvement in MPG.


.....carry on!....

 

Ok guys thanks a bunch!, and I would say my tires have roughly 40%-50% tread left

 

Setting the timing on mine from 12 back to 10 BTDC increased my mpg from 13-14 up to 16-17.5, with 21 highway (75mph average). It also gained a noticeable power increase.
I use Sea Foam about every 6 months.