So, over the weekend I drove home for deer season, well down in the Middle part of illinois our lowest grade fuel is 87, now when I went home (northern Illinois) their lowest grade was 89 at every station. I filled up on 89 down here (still cheaper than up there) and I noticed that my truck's response time when I press the gas pedal is amazing quicker.

So I guess my question is in the operators manual (My truck didn't have one when I bought it) what is the recommended grade for fuel that they specify?

Also my mpg's decreased about 8 miles per gallon. Just a side note.

 

All these engines are designed at the factory for 87.
The decreased MPG could be a few factors such as air temperature,load on engine (going up more hills on the return trip , hauling 18 dead anima..i mean food units),and gas quality.

 

Going directly from 87 to 89 will not decrease your mileage that dramaticaly. Consider you are trying to feel that new found acceleration and are using up more fuel. They recommend 87 because it runs fine on 87, and most people wouldn't want to put 89 in it.

 

You may have experienced a quality difference more so than a octane difference. I clearly get better mileage no matter what time of year when running shell, BP, ect... vs speedway. Shoot I can even tell that the motor fires off easier when starting from a 8hr cool off.

Rich

 

Well, I wouldnt really say I was mashing it to get acceleration since I was on the interstate 95% of the time. But I calculated that my milage dropped 5.7 mpg, might be the fact Im do for an oil change too.

Also I always use shell gasoline.

 

Out in the farm country parts of Illinois and anywhere in Iowa, I'd be willing to bet the 89 you grabbed was 10% ethanol. That would account for the drop in mileage. When I have seen 10% ethanol available, it has been a dime cheaper than regular at the same station.