Can anyone tell me the most fuel in-efficient way to drive? I got lots of town, and AC/Heat on, but are there things you can do to decrease your mpg?

 

You don't want to cause engine ping. The lighter the load, the less likely it'll ping/knock. Mixing different octanes is acceptable. 1/2 tanks of 87 and 93 will yield an equivalent 90.

 

So by what everyone is telling me, I really should just siphon the gas out. Driving with 87 seems like a bad idea. Would a shop be able to drain the gas?

 

Our fuel tank design makes it difficult to put a siphon hose thru the filler tube but a shop could probably do it. But I think you would be fine for a bit just taking it easy and listening for ping/knock. Even if you refill with 93 at 3/4 tank you'll have close to 89 (~88.5).

You could always pull some timing with the tuner.

 

Don't our cars have an anti-siphon mechanism in the fillerhose?

How low was the tank when she filled it? If it was like half tank of 89, and she put 87 in it, then you're only like 1 point off. Just saying, it's probably not as bad as you think..

 

I think I would drive it until you have 1/2 tank and fill up with 93 octane. Just just keep the rpm's down as much as possible and accelerate slowly. Listen for the ping and if you hear it do something different. Not a huge deal!

 

+1, just baby it & you will be fine. DO NOT put octane booster like stated above.

 

No, no. You misunderstand. I just tuned my car, and it has an 89 tune. But I have almost a tank of 87.

 

If you have a handheld tuner, then retard the timing 2 degrees.

 

I didn't misunderstand, you misunderstood my statement.

If you had 89 in the tank and your mom put 87 in the tank, unless you were running on fumes, there was still some 89 in the tank which would have mixed with the 87 and raised the octane level... Your probably fine to run it.

Just do like everyone has said, run a few gallons out of it and put some high-test in it to get the octane rating back up.