So on my rpad trip from MN to AZ we filled up in parts of new mexico and he southern states and they had 86 88 and 90 octane gas? to be safe I filled up my girlfriends civic with 88 and paid the extra 15 cents a gallon. Is 86 safe to use in our trucks? I have always been told nothing less than 87 and to be honest until that trip i had never seen less than 87. So....?

 

Ive seen and used 85 octane in south dakota without any issues, it worked great!

 

Perhaps it worked great, but the 3.7l manual says basically to use 87 octane no matter what. On the 25 gallon tank on empty, that means to throw roughly 6 gallons of premium into the tank. No big deal.

 

cheap gas= bad performance and mileage

 

The Octane rating and performance have nothing to do with each other in a stock motor. All new engines are equipped with Knock Sensor (peizoelectric microphone) that detect such and automatically retard engine timing through the ecu.

A one point drop in octane is fine. Your motor will adjust accordingly if needed. Octane rating is the fuels resistance to detonation.

Now if you had a fully built and tuned motor this is another story.

 

good thing I dont have a 3.7 then, lol! Schissler is correct.

 

High altitude means less oxygen in the air, so you can get away with a lower octane rating. You'll also get better MPG and less horse power at higher altitudes.