Okay, this is really p*****g me off! I filled up my VE with 93 last week and noticed that i got a huge increase in mileage and it seemed like she had more bottom end. It also seemed to run a little rough, if you can figure that out! Fast forward to this week and they're asking for low grade what they were charging for the good stuff a week ago! Now she seems to run smoother, but I'm getting horrible gas mileage, about 150k less than I did on the good stuff. Anybody have the same problems or any idea's? Also, when I hit 110k or so the steering wheel really starts to shake, I hope it's only the tires needing to be balanced.

 

I've read on these forums that the ECU gets used to the type of fuel you use the most and when you all of a sudden switch to a different octane it takes the ECU some time to adjust.

However I switched from 89 to 93 a few times and noticed no difference in the idle really.

 

i sweitched from ow grade to 89, and it feels as though ita got a rougher idle at the light, but it drive a lot nicer, and i also do have better mileage,

i also had a problem with a vibration at about 80mph, but the comp balance didnt pick up anything, so i bought new tires

 

Did that help?

 

Hmmm... I've heard that too. But I kinda blew that off as But I went from 89 to 91 octane on my last fill-up, and my car seems to be 'hobbled' a bit. I'm hoping it's just coincidence and that my injector that I keep meaning to replace is acting up.