Regular Unleaded or Premium Unleaded?

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I use 87 in my truck. I used premium for a while, but the increase in MPGs did not offset the increase in fuel price. Does anyone have any fact based evidence that indicates long term engine damage, to a 4.7l Toyota endings, from using 87 octane fuel? I believe ever increasing amounts of ethanol can cause certain types of wear, but I don't believe using 87 octane does anything but prevent slightly higher efficiency.

Long term? I've got 16 years and (as of this weekend) 277,000 miles using regular with ethanol. Absolutely zero issues.
 
Only thing about mid grade is the fuel is mixed with a "union valve" so if theres bad gas in either tank you're gonna get some of it. I always use the newest stations in town as they have the newest cleanest tanks with the least amount of crud in the bottom.

This is after working 2 summers for the company that replaced leaking tanks.

Never ever buy gas while the refill truck is present as there fill tank goes to 8 inches off the bottom and stires up all the gunk.
 
PN's for what?

Ok, so it's my understanding that in ~2003 the premium fuel reqmt was no longer in the owners manual or inside fuel door.

I assume toyota changed some parts in the injectors or sensors somewhere?

Just curious if there are different part#s for a 99 vs 03...
 
Mine drinks 87 and loves it. Still manages to deliver around 14MPG in around town driving. Better on road trips. Worse when towing [shocker!]
 
In 2003, they went from a 4-speed transmission to the 5-speed transmission. In doing so, they could achieve the same fuel economy on 87-octane as before. Previously, they had to have 93-octane to get the rated mileage out of the 4-speed slushbox. Then, in 2006 when they added VVTi, they were able to bump up the rated MPG due to the increased HP/Torque combined with the 5-speed trans.
 
Ok, so it's my understanding that in ~2003 the premium fuel reqmt was no longer in the owners manual or inside fuel door.

I assume toyota changed some parts in the injectors or sensors somewhere?

Just curious if there are different part#s for a 99 vs 03...

Wow....there are a lot of parts in the EFI system for me to check. I'd need a bit of time on that.
 
I looked at premium this evening just because I have been reading this thread... And here in the DC area... it was between .45 and .55 cents more than the 87. I buy between 50 and 60 gallons of gas a week. That would add up.
 
I know Christo is against using regular, but I don't know what is different from an older vs newer 100 that changed the fuel std except tranny gearing.
 
I know Christo is against using regular, but I don't know what is different from an older vs newer 100 that changed the fuel std except tranny gearing.

Christo is also at 5000 ft and his regular is what? 85 octane? Which is fine until you come down the mountain.
 
It’s not an “octane sensor”. It uses the knock sensor to detect knocking & its not necessarily audible. If you do hear knock than you have a much more serious condition.
Here is some good information on this subject.
The "octane value" is a term coined by Todd Day to refer to the memory address that is used as a longterm timing trim. If the ECU hears a moderate amount of knock for a long time, or alot of knock for a shorter amount of time, it will keep reducing the value in this memory address. Normally set at 255 (FULL), it will keep getting reduced as long as it hears knock. This could be due to just getting a bad tank of gas, or perhaps running more boost than you are tuned for. But, even if you fix the problem, by filling back up with good premium fuel, or turning down the boost, the "octane value" can take several hundred miles to work its way back up to "FULL" value again.
Dean

@DMX84 OMG I have not hear/read Todd Day's name since, well, 2002 or so?!!? And LTT, wow, takes me back to my 97 TSI AWD (which I still have) - were you on the Talon Digest?!?
 
I understand most posters here have a Land Cruiser. What gas should I run in my 07 LX470? I've only had it for several months, but so far I have only used premium 93 octane. Can I switch to just regular from now or is it unsafe at 118k miles?
 
I understand most posters here have a Land Cruiser. What gas should I run in my 07 LX470? I've only had it for several months, but so far I have only used premium 93 octane. Can I switch to just regular from now or is it unsafe at 118k miles?

If you lived is Colorado and drove up mountains I would use Premium. If your in flat Illinois you can use regular. I'm kind of different, I use what the people that made the vehicle state I should use in the owners manual. You will get owners that have used regular for 100,000's of mile and claim not problems.
 
I've been running 87 in both 100's for over 2 years now...no issues at all. The LX belonged to my mother for 10 years and she only ran premium in it. When we took it over and started with regular, no noticeable change in mileage or performance.

Driving to HIH6 later this month I will probably throw premium in since I'll be doing about 5,000 miles and lots of high rpms to get up those big hills. :cheers:
 
I track my mileage religiously and conducted a two year experiment with this issue. Regular gas provided definitively lower MPG. The difference was around 10% if I recall correctly.

Assuming my experience is indicative of all 100 series engines, you may not be saving any $ at all by using regular. The cost difference between premium and regular varies from around 5% to 15%.

Price spread between regular and premium gasoline has changed over time - Today in Energy - U.S. Energy Information Administration (EIA)

I use premium always now (91 in my area). When running regular, the marginal savings in gasoline costs is decreased by a drop in MPG and may introduce light knocking in the engine - not enough to throw engine codes, but perhaps enough to introduce a slightly higher rate of wear on internals. I'll pay an extra $2-4 every 250 miles to ensure I'm not hurting long term reliability. I want to hit 500k on this rig. :) Take into consideration that most our tires alone cost around $5 per tank of gas and that small bump in gas price may not seem so big.
 
I track my mileage religiously and conducted a two year experiment with this issue. Regular gas provided definitively lower MPG. The difference was around 10% if I recall correctly.

Assuming my experience is indicative of all 100 series engines, you may not be saving any $ at all by using regular. The cost difference between premium and regular varies from around 5% to 15%.

Price spread between regular and premium gasoline has changed over time - Today in Energy - U.S. Energy Information Administration (EIA)

I use premium always now (91 in my area). When running regular, the marginal savings in gasoline costs is decreased by a drop in MPG and may introduce light knocking in the engine - not enough to throw engine codes, but perhaps enough to introduce a slightly higher rate of wear on internals. I'll pay an extra $2-4 every 250 miles to ensure I'm not hurting long term reliability. I want to hit 500k on this rig. :) Take into consideration that most our tires alone cost around $5 per tank of gas and that small bump in gas price may not seem so big.

Exactly how I think about it. You gain in mpg what you loose in $ but response at least at this altitude feels better. Hell i even run premium in my lawn mower and snow blower.
 
I track my mileage religiously and conducted a two year experiment with this issue. Regular gas provided definitively lower MPG. The difference was around 10% if I recall correctly.

Assuming my experience is indicative of all 100 series engines, you may not be saving any $ at all by using regular. The cost difference between premium and regular varies from around 5% to 15%.

Price spread between regular and premium gasoline has changed over time - Today in Energy - U.S. Energy Information Administration (EIA)

I use premium always now (91 in my area). When running regular, the marginal savings in gasoline costs is decreased by a drop in MPG and may introduce light knocking in the engine - not enough to throw engine codes, but perhaps enough to introduce a slightly higher rate of wear on internals. I'll pay an extra $2-4 every 250 miles to ensure I'm not hurting long term reliability. I want to hit 500k on this rig. :) Take into consideration that most our tires alone cost around $5 per tank of gas and that small bump in gas price may not seem so big.

Yep, I found the same result and use premium now.
 

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