Premium gasoline

Gas is gas. The only difference between the brand is their additive package. That's it. Chevron is the cream of the crop for keeping everything in you're engine clean and that is why it costs more. Pay now or pay later. I have a frind of mine that has hauled gas for years. That is where I got my info from not counting other gas haulers I have talked to. I've always used Chevron when it is available. Texaco is the exact same gas because Chevron owns Texaco.

 

Gas is Gas. Please let this not turn into another Amsoil debate.

 

I run premium at 7000ft because I have tried 87 and 88 and it may be hard to put my finger on but my 2.7 just "seems" to run better with premium. I notice a very slight difference in throttle response and power whenever I change over to lesser octane ratings. Money wise? Premium saves me nothing. I haven't noticed any difference in mileage but that might probably change at sea level. I spend all my time at higher elevations between 4000 and 9000 feet above sea level.

 

If you reset your ECU after you arrive at that 7000ft elevation, your car should run better as the ECU will have to recalibrate the fuel trims for the lower air density. Same wil dropping elevation.

 

I have done that a few times. My truck does run better on premium but once in a while I switch to the lower octane stuff and as I said, the difference is very slight but it is there it's just almost imperceptible.

 

As these engines like any engine for that matter ages. Carbon builds up on top of the pistons which increases compression. Really bad build up will benefit from higher octane. While others may see little to no difference. I personally run 89 just because.

 

Your conclusions are the opposite of the octane need of your engine. The higher the altitude the less octane needed, hence regular in mountain states being only 85 octane. Thinner air means lower cylinder pressure. The 2.7L is low compression and doesn't need high octane, especially at high altitude.

I run 85 octane at 5500+ with great results, I run alcohol free when I can get it, which isn't often but that helps my mpg, is the premium you buy alcohol free?

The ecu adjusts the fuel delivery in closed loop continuously, no need to disconnect the battery

 

You're right. My only point was that my truck does seem to run better with the premium. As for why? I have no idea but I do notice a difference when I use regular. It is very slight though.

 

Also installing a external fule filter isn't a bad idea. I put one in when I upgraded my fule pump.

 

get a scantool, setup timing advance on it and watch. see if it changes when you use lower and higher octane fuels. if it does, then your fuel is combusting at such a degree that it provides better engine performance. not enough to increase horsepower though.

 

I have a Scan Gauge in the truck. I'll check that out. Thanks. There is no ethanol free in my area. I wish there was.

 

mine has an external fuel filter. It's a PIA to change because it's under the intake but it's there. I'll be changing mine in another 10,000 miles per Toyota's recommendations. They say every 30,000.

 

I would find it hard to believe that this engine is carboned up considering the maintenance it has had since new. Until I got it 20,000 miles ago it never had anything put through it but Chevron. Of course my dad drove it like a typical "old Man". I doubt it ever saw anything past 2500 rpm until I got it so it might be possible but I have cleaned it out quit a few times since I got it with Seafoam, Techron, BG44 and now Amsoil's fuel treatment every 4-5,000 miles.

 

actually we all have two, one internal to the tank which is a "sock" over the fuel pickup tube and the other which is external. on 3.4 its on the frame rail under drivers seat area and on 4 cylinders its mounted way up under the intake manifold where you can barely see it or access it.

when you replace your filter you should do my 4 cylinder fuel filter relocation mod seen here: https://www.tacomaworld.com/threads/diy-2-4l-2-7l-fuel-filter-relocation-mod.349406/

 

I don't see why people struggle with the fuel filter on the 2.7L. I've done mine about once a year and it doesn't take more than 30min for me. And I don't have small hands at all.

Trick is to use stubby wrenches on the banjo bolts, and attack the mounting bolts from outside the manifold with a few extensions.

 

The desire to replace a lifetime fuel filter is still strong.

http://www.supramania.com/forums/content.php?121-The-great-fuel-filter-myth

 

I thought I read somewhere its pointless to run anything higher in a 2.7

 

I have to put 91 because I'm living that boosted life, but that extra $$ is worth the whining from the SC

 

That owners manual says so, has for decades.