Mid Range gasoline.

[Fatstrat]

Both of my vehicle are early 2000's (2001 and 2002) vintage. Very well maintained. We use Quiktrip gas almost exclusively. Which is the most popular gas station in the Tulsa area. And claims to have "Top Tier" gasoline.
Generally we run the lowest octane regular. Especially when gas prices are high. But in my 2001 Ford F-150 w/4.6 V-8, I noticed that the quality of gas seemed to be hit & miss. Although it generally runs OK on it, it misses at idle on some tanks.
Now that gas is a bit cheaper, I've begun running the Mid Range octane gas. And have noticed a marked improvement in how smoothly my engine runs. No more missing at idle. Especially after the 2nd tank. Assume it took 2 to get all the lower octane gas out of system. But so far I have detected no improvement in fuel mileage.
So after this I suggested my wife try it on her 2002 Trailblazer. Same results. So, if you're noticing your engines runs a bit rough and perhaps misses a bit at idle. Maybe moving up to a better gas will help.

[fazool]

bah my car has a high compression engine so I have to run 91+.

I'm in an online car enthusiasts club and several reports have surfaced about EGR and PCV damage along with the smog sensors, so I don't take the chance usually.

[architype]

We have a local quick stop gas and "grocery"...(mostly crap food), that has a good reputation as a great place to work and owned by a local family. They have probably over 100 stores locally and in the surrounding states.
I'm not sure where they get their gas from, but if I run more than a couple tankfuls of regular, my check engine light comes on. The truck still seems to run fine, though. If I switch to Shell or Chevron or BP, the light will go off after about one and a half tanks.

Try running a couple of tanks of regular octane from one of the big oil companies and see if your truck still runs rough.

[harmonics101]

I don't know if its only me, but I refuse to buy gas from Quick Trip, 7 11, Safeway, CostCo, Walmart,

I go with Texaco, Connoco, Shell and Mobile, 93 Octane,

H

[Wardo]

The ZZ4 crate motor in my car needs 94 therefor it don't get driven much no more plus I got a lot of timing in it and no vac advance...lol

The 4.6 in my 2010 150 seems happy on 87 and makes good power.

[Long Jon]

I'm always learning more new stuff here....

I had no idea you could buy various kinds of dodgy generic gasoline in the States.

Here in Britain it's strictly the big name brands (if you count "Jet" and "Q8" anyway).

I run a diesel and have "proved", (to my satisfaction anyway), that it gives better MPG on the slightly more expensive "super diesel".

[Brucebubs]

Here in Australia our `Regular` unleaded is 91 octane, then we have `Premium` which is 95 octane and finally `Premium Hi-Octane` which is usually 98 octane but I noticed a fuel outlet near me labels theirs as 100 octane.There was talk of phasing out the 91 here in Australia and just selling 95 and 98 - don`t know what happened to that idea. BTW Japan has had 100 octane unleaded for many years before Australia switched to unleaded in 1986.

[Bucc5207]

Originally Posted by Brucebubs

Here in Australia our `Regular` unleaded is 91 octane, then we have `Premium` which is 95 octane and finally `Premium Hi-Octane` which is usually 98 octane but a noticed a fuel outlet near me labels theirs as 100 octane.There was talk of phasing out the 91 here in Australia and just selling 95 and 98 - don`t know what happened to that idea. BTW Japan has had 100 octane unleaded for many years before Australia switched to unleaded in 1986.

Y'all measure octane differently in Oz than we do in the US, and your number is 4 or 5 points higher for the same fuel.

[The Growler]

OP - sounds like you're doing it right. Read your owners manual and use the lowest octane recommended, unless you see an issue.

Many people mistakenly think that higher octane is better, but unless needed, is a waste of money. You could actually get slightly worse mileage on higher octane as it is harder to ignite.

[BTF]

Ever since Chevron pulled out of our region, I've been unhappy with the locally available gasoline. I always felt that their Techron additive truly helped keep my engine clean. I use either Mobil or Shell, but where Chevron put Techron in all octane levels of their gasoline, my local Shell dealers says their cleaner is only in the Super grade, and I've still to figure out what Mobil does...

We had two local dealers who sold 100% gasoline rather than that wretched Ethanol blend. Both of them went out of business. I was actually warned by my dealer not to use the top octane level, but my vehicle does seem to do well with the mid-grade.

Thanks for the tip!

[SongwriterFan]

I use QuikTrip or Sam's Club or WalMart gas exclusively in the lowest octane and have never had an issue.

The engines are the 3.0L DOHC Duratec by Ford (used in many Taurus variations).

[bmc]

I remember when midrange was introduced back in the 90's. If my memory is right, what they actually did was introduce a lower grade fuel and made the previously low grade a newly marketed mid grade. The raised the price for it and introduced the lower grade at the price of the now mid grade.

Anyone else recall that as happening?

[Bingoccc]

I always get a brand name. I don't think the gas comes from a different refinery but I do believe the additives (I'm NOT talking about ethanol) are better in the brand names. For years I used high test. Then cars started getting their little computers that make engine adjustments on their own. Now I strictly use the octane rating listed in the owners manual. That is what the vehicle's computer is calibrated to.

[Fatstrat]

Quiktrip is a brand name in this area. They by far have the most stations and set the prices for the region. But I admit that I have no idea where they get their gas. Other than it probably comes from the refinery here in Tulsa.

[KevWind]

The other thing that comes into play especially at cheapy stations is the condition of the fuel storage tanks
If they have any contaminants sludge etc. or things water can significantly degrade the octane of any ethanol blend.