filled up with 89 to test the difference.
My 97 is decent on gas, on average I get around 25mpg or so. Good portion of that being highway though. Worst ever mpg was 17.4 and my best is 28.6. The 04 is not so kind on gas around town, I have no idea how people get 30mpg from the L67 on the highway, best I've ever gotten with it was 25.
Heres a graph from the 97
https://www.fuelly.com/driver/leprec...arlo/fuelchart
Heres a graph from the 97
https://www.fuelly.com/driver/leprec...arlo/fuelchart
My Contribution to this thread below (Check it out 
It could save you $'s +) 
It could save you $'s +) - Gasoline Information, Octane Levels - Exxon.com
<cite style="color: rgb(0, 128, 42); font-size: 14px; font-style: normal;">Quality Fuels, Gasoline, Gas, Lubricants - Exxon.comfuels_quality_gas_faq.aspx</cite>
Why should I follow my owner's manual and choose mid or high-octane fuel? Isn't gas justgas? To get the best performance out of your vehicle, you should use ...
- Premium vs. Regular | Car Talk
<cite class="bc" style="color: rgb(0, 128, 42); font-size: 14px; font-style: normal;">Car Talk › Car Info</cite>
In other words, it's a form of protection for high compression engines. Q. So, I should usehigh-octane gas to prevent pinging? A. High-octane gas will prevent ...
- Paying a Premium for High Octane Gasoline? | Consumer Information
<cite style="color: rgb(0, 128, 42); font-size: 14px; font-style: normal;">http://www.consumer.ftc.gov/.../0210...-premium-high-octane-gasoline</cite>
It may seem like buying higher octane “premium” gas is like giving your car a treat, or boosting its performance. But take note: the recommended gasoline for most cars is regularoctane. ... Should you ever switch to a higher octane gasoline?
- The Truth about Premium Gas | When to Use Higher Octane Gasoline
<cite style="color: rgb(0, 128, 42); font-size: 14px; font-style: normal;">www.kbb.com/car-advice/articles/premium-gas-when-and-why/</cite>
An advice article from Kelley Blue Book on the truth about premium gas. Details on the best time to use a higher octane gasoline, and what it contains to help ...
Monte Of The Month -- August 2014
Joined: Sep 2008
Posts: 25,145
From: Southeast PA
A dirty air filter would actually help your MPGs by restricting the amount of air to your MAF and the computer sending less fuel.
Since you are noticing a scent, I think you are running too rich and detonating poorly. You should definitely take a look at doing the fuel filter, checking the fuel pressure, remove a plug and just look at it to make sure it's still okay, etc.
Since you are noticing a scent, I think you are running too rich and detonating poorly. You should definitely take a look at doing the fuel filter, checking the fuel pressure, remove a plug and just look at it to make sure it's still okay, etc.
Thread Starter
Joined: Nov 2011
Posts: 1,043
From: massachusetts
Ill have Paul check the pump maybe the 30 dollar salvage pump is biting the dust after 2 years. Should I upgrade to a k&n drop in filter to help get more air in on the highway. Because when I go back and fourth to school my car uses just under a quarter tank to do 110 mi
Monte Of The Month -- August 2012
Joined: Apr 2011
Posts: 6,074
From: Seattle
The difference in performance you notice probably has to do with the amount of ethanol added to the fuel. A 'rotten egg' smell doesn't always indicate a problem. A fuel with a high sulfur content will cause this. Try filling up a couple of times at a different station (with 87 octane) and see if the smell goes away and performance improves.
Monte Of The Month -- November 2012
Monte Of The Month -- August 2015
Monte Of The Month -- August 2015
Joined: Aug 2011
Posts: 4,793
From: Ann Arbor, Michigan
I ran the K&N drop in filter element in my 03 SS.
Really, although you're talking 1990's technology versus mid 2000's. Best I've got in my 06 with the V8 is 24.5mpg; that was almost all highway cruising at 70mph. So, that's basically the same as what you run and Keane's 04.
Keane, I would think you should be getting higher than 25mpg. That seems poor to me although I'm not sure if the supercharger is a factor; not familiar with that version. I know, in my 03 SS with the NA 3800 V6, I used to easily get up around 28mpg highway. Didn't really keep track of mileage as much back then so I honestly could have gotten higher than that and not known.
I can say Fuelly is great for keeping track of fuel mileage. I use it for both of my cars now.
I can say Fuelly is great for keeping track of fuel mileage. I use it for both of my cars now.
Not sure, I remember other L67 owners reporting 30mpg, I cruise at 70 on the highway and the best I've gotten was 25mpg, maybe if I slowed it down a bit i'd gain more mpg. But that's not happening.
Joined: Mar 2013
Posts: 169
Hi all what do you think about running ethanol free gas in my monte? I have the 3800 engine. There is an oil and propane company about five minutes from where I live and I just recently found out that you can fill up there if you want you just have to ask them. It's about 10 cents more a gallon but its ethanol free and I know of a lot of people who hate ethanol. So what do you all think? Should I try it? Any potential risks with switching from the gas I have now to ethanol free gas?