Wow! read this entire thread and not sure where I lie? I have been told that 87 octane should not be used in the Endeavor so I have kept using 89 that is available here and occasionally put in a tank of 91 or 93 which I understand should work fine because of the adjustments of the sensors. I have been told about the gas mileage being better with the higher octanes...going cross country here in the US and using a mixture of 89 and above depending on availability in the State we were in, I did not notice any difference as the mileage stayed pretty constant.

I would like to add a point that some consumer groups point out that there is NO difference in the gas in the different octane listings at the pump, however I still find this to be wrong. I have a 2005 BMW Z4 also and it requires 91 or better and the preformance has stayed HIGH so I will continue to use 91 or better in the Z.

As for my Endeavor I will stay with the mid grade of 89 and mix in some premiums from time to time. 33,000 miles and still going strong so why change? If only I can get the steering problem diagnosed and fixed I could relax and enjoy the winter with my new Michelin tires!

done in PA

I used to use mid-grade on my XLS AWD until gas prices went up. I've been using 87 Octance now for about 6 months and have noticed nothing different. Live in STL so its been through all different kinds of weather and the 87 octane works just fine.

As far as i know the rotten egg smell means that your catalyst converter is starting to go bad...if you have that smell you might want to get your exaust checked out

first... lower octane gas will not damage anything on the endeavor whatsoever.
it IS designed for higher octane, but it also has knock sensors. it will retard the timing to quell the "pinging" that will occur with lower octane fuel, although you will suffer a loss of power and probable minute loss of milage. Having said that, it IS designed for higher octane, and if you cant afford the extra 5 bucks in gas you probably shouldnt have purchased the truck.
Second, a rotten egg smell does NOT mean your catalytic converter is failing. quite the opposite. The rotten egg smell usually occurs during overfueling of the catalytic converter (i.e wide open throttle). The sulfer content of the fuel is what is causing the smell, not the converter. if you suffer from sulfer smelling exhaust, use a different brand of gas.

Man, having someone else on here who knows their stuff is awesome.



Case in point: My mom drives a 2004 Stratus R/T (Eclipse) and she doesn't use premium. I borrowed it, filled it with premium, and she noticed a slight difference in the performance.

I put the octane gas that the manual calls for. Thankfully it's the lowest octane.

But like the brew man says, if you can't afford $5 on fillup, you shouldn't own the vehicle.

Not to confuse the issue but as stated previously the higher the compression ratio the higher the octane level required. Most of you in the US do not have the same engines as we have overseas (mainly the GDI) even if they are the same model. GDI engines run a 10.4:1 compression ratio and thus require 96+. So I would say look at your own vehicle specs and as a rough guide use 87 if compression lower than 9:1, 91 if between 9 & 10 and 96 if higher than 10:1.

Contaminates will also come into the picture in the long run but there is such a wide mixture across the globe it is hard to generalise. Put it this way, you get what you pay for and listen to the mechanics, they see the results.

Jim

Personally, I would notice a slight ping when i used 87 octane on my LS 2WD, it wasn't extremely noticeable, but when I increased the octane, obviously, the ping went away. Since I assume that any slight ping wouldn't make a heck of a difference over a short time, but I plan on owning this vehicle for many miles, and I wish to not have to put as much money into the engine. So, Premium it is!

DOES anyone have a PINGING noise, while using Premium GAS???? any info helpful

I have been running 87 octane and notice no major problem...it still has plenty of power with in-twon mileage about 16 mpg. Don't know if a higher octane would improve the mileage or not. If it would, I might consider the higher octane.

The pinging you are referring to is knock, and that's not a good thing.

What is a KNOCK" caused from??? and what can i do to improve it??

that question has already been answered for you. Ive already told you to use premium gas if you experience "pinging".
If you dont listen to the advice, why keep asking questions?

Wait, manybrews...I quoted you again! This is in response to the previous questioN!

Premium gas is waste unless you are running and endurance race! 87 octane is fine and if it's NOT the ECU will throw you a check engine light! For goodness sakes let the horse die in peace!

I also have a 2004 Nissan Titan and it gets 87 octane and runs just fine!

Seeing how the subjected hasn't been discussed for 8 months, i figured it was dead.

I've had my Endeavor for about 1200 miles (bought it with 8100 miles on it). I've been using only 87 octance and the car runs great. I've averaged 20 mpg in combination city/highway driving (yesterday's fillup revealed 19.6 mpg).

The manual ways that 91 octane is recommended, but in Ohio all I see is 87, 89 and 93. Octane boosters are stupid expensive from what I've seen.

will it "run fine"? yes.
will it run at its maximum potential? Not a chance. The endeavor is prone to light pinging when you DO use premium.

once again, people dont pay attention to the label "premium recommended".. its not there to be pretty. the engineers are smarter than most consumers, and have decided the best choice for your engine is premium.
Ill bet money your car pings badly, and you either cant hear it, or dont know what it is you're listening to.

"once again, people dont pay attention to the label "premium recommended".. its not there to be pretty. the engineers are smarter than most consumers, and have decided the best choice for your engine is premium.
Ill bet money your car pings badly, and you either cant hear it, or dont know what it is you're listening to. "

"Recommended" isn't the same as "required." I've owned a car that "required" premium before. Two in fact. The Endeavor doesn't "require" premium.

I sure know what engine ping sounds like. I'm not deaf. It's not there. At least not in my Endeavor.

its there. Never heard an endeavor that doesnt ping lightly, and ive driven a thousand of them. hell, theres a software update for it on the earlier models.
the earliest models, when used with low octane fuel ping consantly. the later ones with the updated fuel map ping about half as much.

and you're right, you dont "need it". Unless you want the full potential of your endeavor to be exploited.

also, the only difference between required and recommended is that on the latter the engineers assume people dont care as much about maximum performance. I.E. the EVO "requires" premium to get maximum performance. It doesnt actually "require" it, as it will do the same thing as the endeavor when it experiences ping... it will retard the timing.
But on an EVO thats a no-no, whereas on an endeavor its not such a big deal.
the fact still remains that for both premium should be used, as thats what the engine was designed for.