techrep

Nothing !! run 87 and you will be fine...

GRAYM

2003 used regular for 13 years no issues

zippinbye

Running less than premium lowers the engine's output potential. Really only a factor at wide open throttle and most of us would never notice unless tracked by a chronometer in an acceleration test. We have a "beater" 98 LS 400 (VVTi came to the LS in 98) with 330,000 miles. It has never seen premium fuel after 40,000 miles as far as I know. Just the opposite of our GX, I flog the LS like a teenager, full right pedal with frequency. Including buried speedo on the Silver State Classic highway last year. Aside from annoying climate control issues, the car has never faltered. As my Aussie friend says regarding his VVTi Land Cruiser, "the computer will retard timing to avoid predetonation running kangaroo ****!" Of course fuel grade is a matter of personal choice and comfort level, but it's unrealistic to expect greater longivity by running premium. Either side of the argument, there's a positive. More horsepower is good even if you don't need it, as is more money in your pocket.

surferdp

Have run both and compared mpg on long trips; can't say I noticed improved performance with premium and mine runs great on 87 octane

NTH

For putt putt around town and highway driving, I run regular. If I had to tow or do a lot of hills she gets premium.

lesz

As stated earlier, a major factor in determining whether premium or regular fuel is recommended has been the EPA requirements to get the highest EPA emissions ratings. If you look at various Toyota/Lexus engines over the last 10-15 years, you will find that, with the same engine, the recommended fuel has often changed from one year to the next, and those changes correlate with changes in the EPA requirements.

Further, even when premium fuel has been recommended for the GX 4.7 liter V8, it has just been a "recommendation", but Toyota/Lexus has also stated that 87 octane regular is sufficient.

Switching back and forth between premium fuel and regular fuel depending on whether driving is "putt putt around town" or whether driving involves "towing or a lot of hills" is not likely to accomplish much (except to drain your wallet of the extra cost when premium fuel is being used) because, when you switch fuel grades, it is going to take several tankfuls of fuel before the VVT-i adjusts itself to the change in fuel grade.

lukasbasic

I hope this wasn't asked here like a million times. so where I live, all gas stations have 87,89, and 91 ethanol free only. the price difference between 87 and 91 ethanol free is like 80 cents per gal. (87-89 like 10 cents)
now I know that ethanol sucks. but my 2006 GX 470 has 144k miles and I don't feel like paying 15usd more every filling. unless it will prevent me expensive repairs down the line.
this car is old, but I would like to use for a while longer, especially since its my only vehicle to tow stuff like boats, atv's etc.

EddieK05

Regular is fine.

drowssap

This is funny that I just came across this thread! I have been testing the gas for the last 7 tanks. First you mot definitely gas use regular but what I can tell you is that the engine is tuned to operate best with premium. The last tank I noticed that I dropped from about 400 miles a tank to 310 with 89! Same driving conditions.

2008

Regular is fine. Couldn't have said it better myself. Probably no significant difference in performance or economy. I think the premium gas has more to do with the emissions system tuning than anything else. Not a big deal either way, I run regular. When I owned a BMW that asked for 89 minimum and higher recommended I always put 91 in.. not in this car though.

BradTank

I've been using 87 octane for a while now also with no problem. It does seem like they go above and beyond to gouge people on 91 octane these days. When I was growing, it was like 10 cents more gallon. I wouldn't think twice if that was the difference in price.

Supposedly older cars before they had knock sensors, you had to be careful with matching the octane to avoid detonation, but modern cars can adapt to it just fine.

Htony

If a driver does not feel the difference in his cars behavior when he switches fuel grade, or did not notice less MPG then why not?

Htony

Knock sensor has a limit too. Many drivers don't /can't feel knocking or pinging when they drive.

BradTank

But with a knock sensor, the car's computer can back off on the timing and adjust automatically.

BradTank

Octane alone is not going to account for that difference. Other factors were at play.