I don't know exactly what is happening, but in the last week or two, my onboard fuel mileage meter on my 2002 Liberty V-6 has crept up from 16.3 MPG to 17.4 MPG as of yesterday. My driving habits havn't noticably changed, and it is still hot here...in the 90's daily, so I am still using my A/C. I am still using the "relatively" cheap 86 octane gas. ($3.07/gallon!
) It had been at 16.3 since the larger tires and computer re-program a couple months ago.
The only thing different is that last time I changed my oil, I switched from a 5W30 oil, which I believe was Coastal brand from Autozone, to a 10W30 Quaker State. I did this just days before the mileage started creeping up.
I wouldn't think a thicker oil would improve mileage...and I wouldn't think ANY oil would make that kind of improvement, but I am surely not complaining.
Anyone else ever have something like this happen?
