3.5 V6 Atkinson Cycle engine and the gas grade parade extravaganza...

87 performance is best hands down. got 15000 on mine and have tried all. 87 gives a tad more low end grunt it seems.

 

I'm getting around 25 mpg using 100% gas @ 91 octane but it's about $2.69-$2.79 per gallon....You should get the fuelly app....It's a great way to track your mileage.

Edit: My fuelly link shows less but that was before I figured out how to get more mileage. Click on it and it will show you a little about the app.

 

Blah blah blah higher combustion blah blah waste blah

 

This....

I wouldn't say I hear loud knocking with 87.. but I definitely have more of a low end "grunt" as someone perfectly put it... It's almost like the engine shakes a bit more around 1800-2000 rpm.... And apparently I'm not the only one who noticed this.. I try to use always the same pumps when I post attention to this stuff.... Anyways everyone is entitled to their own opinions and do whatever they want with their money.. isn't that what our founding fathers wanted? The right to choose your own gas grade freely?

 

When you say premium, you mean non-ethanol?
Premium E10 has more ethanol in it than regular E10...

 

@Knucklegrumble I didn't see this until today. If you don't settle on one type, the engine is constantly trying to adjust to whatever is in the tank at the time. The engine kinda needs steady state to adjust and settle down. Gotta test methodically over time to figure out the best path.

 

Well as I said I really ran 2 tanks of 87 when first bought the truck and the difference with 89 is noticeable even right after the first 1/4 tank... Adjustment made by the cpu are still minimal..

 

.
...^^^... Manual says 87 is ok, but I started using 92 in hot and humid weather due to pinging issues.

Now, I use COSTCO 92 all the time and it seems to ping a lot less under load. Actually no pinging now with 92 octane.

IIRC, the compression is higher too in the 3.5.???

 

Your wasting your money
on anything but 87oct gas. The computer will figure it out and go back to running as programed. You will fool it for a while.

 

I didn't read this whole thread, but not a once did anyone mention higher-elevation drivers. In CO, our pumps start at 85... 85 is just fine at 5000+ feet above sea level for this truck. Just don't fill it up with 85 before going on a road trip to Kansas.

 

with crude prices so low, doesnt that mean less ethanol is in most fuel currently? regardless i do my best to use ethanol free, it just isnt as easy to find every where

 

You have no idea how the programming works. Long Term, Short Term fuel trims will vary based on ethanol content as it tries to hit targeted AFR values based on the o2 sensor readings. As the ethanol content changes, those trims will change, and it will be permanent provided fuel consistency is achieved.

Secondly, total advance timing is a calculated result based on a base timing map, a timing adjustment map, and any current timing corrections as a result of detected knock. If you are consistently knocking with 87 octane in certain load/rpm ranges, learned timing with have retarded values in the timing adjustment table and until the knock is corrected, the timing will remain retarded.

If you upgrade fuel, it will NEVER advance beyond what the tune is designed for, but without knock, you will be able to advance timing to the maximum values which translates to maximum power and efficiency. There is no "fooling" the ECU based on what fuel you run. That's just pure malarkey.

 

The land of the Freedom!

Anyway by using 89 the truck performs better than using 87. But again is all about personal preference

 

You are correct in most of this post. You are incorrect in the statement about Toyota not trimming the timing set points. Toyota's code will test and trim the timing based on knock counts. Octane affects knocks. Thus, octane affects timing, which affects combustion, which affects fuel economy and power. Nice post though.

 

I went through 1 tank of higher grade fuel and found my MPG go south, like 15mpg. The truck, at least mine works much better on low grade fuel.

 

Coincidence or bad gas from that particular station.

 

No, I dont think so. It ran fine but the mileage went down and it labored to get up to speed, but not enough that it was in your face. Lethargic would be a better word for it.

 

I've found my gas mileage varies from tank to tank with the same brand sometimes....And I've found one tank of good gas after running 87 will not show up in better mileage. It takes me a couple of tanks.

But it gets the best average mileage with high test...I've been running that Valero high test lately since reading about it being a "Top Tier" gas here on Tacoma World.

I took this picture earlier today after about 15 minutes of driving....Granted it won't stay this high but I average 24-26 mpg on a lot of trips....sometimes even higher.

 

I've got a new baby too and only want the best. I run out the dealer gas and put in just plain unleaded but it said on the pump "May contain 10% Ethonol" I added LUCAS additive to it. Some people sayit helps with milage and keep the fuel injectors clean. I have not noticed any change in mpg and have not heard any noises. Tell me if I need to stop usung LUCAS. There is one gas station in town that sells pure gas but its pricey. I don't drive a lot maybe5k a year in town and a little on country roads but I have seen it 20 mpg a time or two but that was pre LUCAS treatment.

 

Premium fuel, as the concept, is not going to cause this behavior. Fuel trims, timing adjustment or poor power due to "old" gas are the only culprits. Ethanol goes bad fast, and if you fill up with premium at a station that doesn't go through premium often, this is a likely scenario, but it's not an inherent problem with higher octane fuels, and that's a fact.

You would need to run more than a tank at more gas stations to be able to come to any logical conclusion on the matter anyhow.