The label inside my gas cap says, "Use Premium Unleaded Fuel Only."
I follow Jeep's maintainance recommendations to the letter, thus I will only blame Jeep and not second guess myself if anything goes wrong.
By the time you buy the fuel additives, it's cheaper to just buy premium gas. I've tried 87 octane gas in my Passat and it just isn't as smooth. The problem is, it says it needs 91 octane and all I can find around here is 89 or 93. Mixing half a tank of each is too much trouble to save 10 cents a gallon in half of a 14 gallon tank.
Ok, so here's the deal, I put in more research. The Jeep 5.9L engine in question can run on regular fuel, but the folks at the Jeep division of Chrysler programmed the PCM (the car's engine computer) to run on premium only rather than let it behave variably (the way the newest version does, I believe), claiming performance enhancements, so if you want to run it on regular you have to take it to a dealership and have the PCM "flashed" (reprogrammed) for regular. The reason they even have this option is because the Dodge division of Chrysler uses the same engine in one of their Ram pickups, only it runs on regular. That, folks, is why I try to avoid Chrysler as much as possible. (I try to avoid Ford as much as possible for other reasons, even though my Mazda is a joint effort between Mazda and Ford.)
So, extra trouble to save $0.20 per gallon, with a 20 gallon tank, or $4 / maybe $8-12 per month?
That's not the issue. It's now like $300/ month for me in gas. If it was "only" $288 that's not going to stop me from complaining or hurting any less.
$12 a month is $144 a year. That's still not a lot to hurt me. I'm going to spend more on the Millennium Falcon on July 26.
The pain is in the whole price amount: when it was $2.49 gallon for premium, I could fill up for $50 and might only spend $150 / month on gasoline, comfortably driving wherever / whenever I wanted.
Now I'd worry about saving less than what I used to pay per month out of the whole year's gas expenditure? That's simply not the problem. At least this way I don't have to bother with any modification to my Jeep's maintainance.
Yeah, around $12 off $300 is correct. Hey, if you can afford to pi** away your money to the oil companies, by all means, go for it.
I tell you what. I can't remember the last time I filled my tank to full on either of my vehicles. It takes me less that 3/4 of a tank to get to work and back in a week, so I usually only fill it that far.
Over the past coupkle of weeks I've been carpooling with a buddy to work as well. I drive one week, and he drives the next. It saves me between 30 and 40 buck when I don't drive that week.
I always do fillups so I can keep track of my mileage. Plus, it means I have to refuel less often.
Smith's Grocery store has it where if you buy x amount of groceries you get a certain percentage off your gas, $30 you get 5 cents, $60 10 cents and so on. I bought $62 worth of groceries, and got the 10 cents off per gallon when I filled up. They built a gas station on the same lot, so it's right over to the gas pump after food shopping. Regular is 3.88 with discount it's 3.78. Still ended up paying over $100 in one trip.