My mileage meter is getting a little funny. I noticed that i was getting less, and in the next couple days the cel came on and it threw a rear 02 bank one code. It being 10 years old and with 90K miles I just went ahead and replaced all 4 02 sensors, and cleaned the MAF to cover the bases. But the miles indicator is all over the map. It'll show 200 miles to go, then I'll stop somewhere and when I leave it'll show 270 miles to go. I know it varies, but its changing everytime I stop by a signifigant amount and it wasn't doin this before? Any quirks anyone knows about with these things?